WO2009080060A1

WO2009080060A1 - Improved cooling arrangement, device and method

Info

Publication number: WO2009080060A1
Application number: PCT/EP2007/011184
Authority: WO
Inventors: Jorma Manninen; Janne Nurminen; Teppo Aapro; Vesa Kyyhkynen
Original assignee: Nokia Inc
Current assignee: Nokia Inc
Priority date: 2007-12-19
Filing date: 2007-12-19
Publication date: 2009-07-02
Anticipated expiration: 2010-06-19

Abstract

A cooling arrangement comprising a housing having a first portion and a second part. The first portion is arranged to house a component that is capable of generating heat, and a second portion comprising an air flow path. A partitioning wall is thermally connected to the component and the partitioning wall is arranged to dissipate said generated heat from said component into said air flow path. Furthermore the partitioning wall is arranged to shield said component from air flowing along said air flow path for protecting said component from impurities being carried by said air flow.

Description

IMPROVED COOLING ARRANGEMENT, DEVICE AND METHOD

The present application relates to cooling and in particular to an arrangement, a device and a method for providing efficient cooling of components while protecting said components.

BACKGROUND OF THE INVENTION

More and more electronic devices such as mobile phones, MP3 players, Personal Digital Assistants (PDAs) are becoming smaller and smaller while having more and more information stored and/or accessible through them. Users are relying on these devices and becoming all the more dependant on them. Due to the devices' complexity they also have high power consumption and as they are designed to be small and easy to carry around the power consumption becomes an issue of importance.

With the high power consumption come higher requirements for efficient cooling of the device as more heat is generated by the device when it consumes more power. As is generally known, if the device is not properly cooled it can lead to overheating which in a worst case leads to a fire or an explosion, and in any case to a reduced operational efficiency of the device and further increased power consumption.

Cooling is traditionally achieved by a heat sink being placed on or adjacent to the device or object to be cooled. A heat sink generally consists of a material that absorbs and dissipates heat easily, such as metals. This material is brought in thermal contact, either through direct contact with the object or through radiation, and through this thermal contact heat is transferred to the sink and the temperature of the object is thus lowered. The sink dissipates the heat absorbed to its surroundings thereby being able to absorb more heat from the device and maintaining a cooling effect. To further increase the cooling effect of a heat sink its surface can be made larger so that it can dissipate the absorbed heat more quickly. Therefore a heat sink is usually in the form of a collection of thermally connected (metal) fins or other structure providing an extended surface arranged so that air can flow between them.

The heat dissipated from the heat sink is absorbed by the surrounding atmosphere, which usually is air. As air is not a good thermal conductor it limits the amount of heat that can be dissipated from the heat sink and thus also from the object to be cooled. The main factor deciding how much heat that can be absorbed is the amount of air being in contact with the sink. In addition to increasing the surface of the heat sink as explained above a fan can be coupled to the heat sink which forces air over the heat sink thus increasing the amount of air being in contact with the sink and keeping the temperature gradient between the heat sink and the surrounding, absorbing air as high as possible which speeds up the dissipation of heat. Such fan coupled or fan powered heat sinks are very common for cooling electrical components such as Central Processing Units (CPUs) for computers and the like.

One problem inherent in these heat sinks is their size. As the heat dissipation is proportional to the surface the heat sinks tend to be large and therefore difficult to mount on or adjacent to the components. One cooling arrangement such as above is disclosed in US6975509B2 "Computing apparatus with cooling fan" that disclose a cooling arrangement for a computing apparatus including a housing that defines a cavity. The computer apparatus further includes within the cavity multiple computing components, such as a processor, memory, and so on, and a fan for generating an airflow to cool these components. There is a first path defining an air inflow for the fan, and a second path defining an air outflow for the fan. One of these paths is externally ducted to a vent facility in a first wall of the housing, and the other one of the paths communicates with the cavity adjacent the first wall. Typically, the externally ducted airflow is arranged to cool a CPU, which is the component most vulnerable to over-heating. This cooling arrangement is arranged to provide a controlled airflow over certain components and can thus be used to cool more than one component at a varying, but pre-specified rate using only one fan.

Another cooling arrangement is disclosed in JP8263162 that is arranged to cool the surface of a heat generating element and an input device such as a keyboard below specific temperature even when the portable personal computer has the high heat generating element mounted in a flat housing equipped with the input device. This is achieved by a 1st space is formed between the back of the operation part of the keyboard and an electronic circuit board and the surface where the high heat generating element mounted on the electronic circuit board is installed on a different surface from the surface facing the input device; and a 2nd space is formed of the electronic circuit board and an electronic circuit board, and a fan is installed in the housing so that cooling air flows from the 1st space to the 2nd space. On the wall surface of the operation part of the input device, a flow passage is constituted which makes outside air flow in the housing through a suction hole. This arrangement ensures that new fresh and cool air is introduced to the cooling arrangement to maintain the cooling effect.

The environments in which these devices are used are becoming more and more varying, often being outside environments such as in nature. This generates a problem in that as the fan is blowing or forcing air into the device and the air is taken from the surroundings the risks of particles such as dust and dirt being blown into the circuitry is significantly increased and causes a risk of premature failure. Also, as the surrounding air has certain humidity and this air is blown into the device there is also a risk of a higher corrosion rate.

The cooling arrangements above all suffer from these disadvantages

DISCLOSURE OF THE INVENTION

On this background, it is an object of the present application to provide a device that overcome or at least reduce the drawbacks indicated above by providing a device .

This object is achieved by providing a cooling arrangement comprising a housing, said housing comprising a first housing portion, arranged to enclose at least one component capable of generating heat, and a second housing portion comprising an air flow path, and wherein said at least one component being thermally connected to said second housing portion, and said at least one component being shielded from air flowing along said air flow path for protecting said component from impurities being carried by said air flow.

This enables efficient cooling of a component while protecting it in a cooling arrangement having a space saving design.

By realising that the airflow need not be over the components directly to cool them, and that it suffices if the airflow is over a thermally connected element or heat dissipating means the components can be cooled efficiently while still being protected or shielded from impurities, such as dust, other particles or humidity, in the air.

Secondly, the separated airflow and air actuator allows the components in the first housing portion being efficiently protected from vibrations and noise generated by the air actuator

In one embodiment the cooling arrangement further comprises a partitioning wall for separating the air content of said first and second housing portions. This enables an easy and also possibly load-bearing structure to divide the two housing portions.

In one embodiment said partitioning wall is arranged to dissipate said generated heat from said component into said air flow path. This increases the surface available for dissipating the generated heat and thereby enables the over-all size of the cooling arrangement to be decreased.

In one embodiment the cooling arrangement further comprises a heat conductor for transferring said generated heat from said at least one component to said second housing portion for dissipation into said air flow. This enables the heat to transfer easily through or around the partitioning wall without compromising the shielding. This also provides for a slim over-all design.

In one embodiment said heat conductor is an integral part of at least one of the walls that define said first housing portion and an integral part of at least one of the walls defining said second housing portion. This increases the heat transfer, makes it easier to fit the heat conductor and also provides some load-bearing capabilities to the housing

In one embodiment said partitioning wall is an integral part of said heat conductor or is thermally connected to the heat conductor. In one embodiment said partitioning wall is said heat conductor.

In one embodiment the partitioning wall is an integral part of the housing and in one embodiment the partitioning wall is not a heat conductor.

In one embodiment the cooling arrangement further comprises an air actuator for forcing said air flow along said air flow path. This increases the amount of air that passes through the air flow path and thereby increases the amount of heat that can be dissipated into the air flow. In one embodiment said air actuator is one from the group consisting of: a fan, a blower, a piezo element, a loud speaker membrane and a vibrating element.

In one embodiment the cooling arrangement further comprises an inlet and an outlet arranged to define said air flow. This ensures that new, fresh air can enter the system and to allow heat to escape the system thereby further increasing the cooling effect.

In one embodiment the cooling arrangement further comprises cooling fins arranged in said air flow path being thermally connected to said heat conductor, wherein said cooling fins are arranged to support said dissipation of said heat. Cooling fins increase the heat exchange surface and thereby also the dissipation into the airflow.

In one embodiment said housing is further arranged to be connected to a printed wire board (PWB) on which said at least one component is mounted, wherein said first housing portion is arranged to enclose said component upon connection of said housing to said printed wire board. This enables a cooling arrangement to be mounted on a PWB needing an improved cooling system.

In one embodiment said partitioning wall, said heat conductor and/or said cooling fins are each at least partially made of a thermally conductive material, wherein said thermally conductive material is any of a group comprising: metals, plastics, such as Acrylonitrile butadiene styrene (ABS) , Polycarbonates (PC) or Polyamides (PA) , or graphite foil and other thermally conductive materials such as in the form of heat pipe or thermo electric cooler. Other thermally conductive polymers that can be used are Cool Polymers™ and PolyOne™.

In one aspect of the present application the objectives above are achieved by providing a cooling arrangement such as below having the same benefits and advantages as the cooling arrangement above.

Such a cooling arrangement comprises a housing, said housing comprising a first housing portion, arranged to enclose at least one component capable of generating heat and a second housing portion comprising an air flow path, and wherein said cooling arrangement comprises means for thermally connecting at least one component to said second housing portion, and means for shielding said at least one component from air flowing along said air flow path for protecting said component from impurities being carried by said air flow.

In one embodiment the cooling arrangement further comprises partitioning means for separating the air content of said first and second housing portions.

In one embodiment said partitioning means are arranged to dissipate said generated heat from said component into said air flow path.

In one embodiment the cooling arrangement further comprises heat conductor means for transferring said generated heat from said at least one component to said second housing portion for dissipation into said air flow. In one embodiment said heat conductor means is an integral part of at least one of the walls that define said first housing portion and an integral part of at least one of the walls defining said second housing portion.

In one embodiment said partitioning means is an integral part of said heat conductor means or is thermally connected to said heat conductor means.

In one embodiment said partitioning means is said heat conductor means .

In one embodiment the cooling arrangement further comprises air actuator means for forcing said air flow along said air flow path.

In one embodiment said air actuator means is one from the group consisting of: a fan, a blower, a piezo element, a loud speaker membrane and a vibrating element.

In one embodiment the cooling arrangement further comprising an inlet and an outlet arranged to define said air flow path.

In one embodiment the cooling arrangement further comprises cooling fins arranged in said air flow path being thermally connected to said heat conductor means, wherein said cooling fins are arranged to support said dissipation of said heat.

In one embodiment said housing further comprises means for being connected to a printed wire board on which said at least one component is mounted, wherein said first housing portion is arranged to enclose said component upon connection of said housing to said printed wire board.

In one embodiment said partitioning wall, said heat conductor and/or said cooling fins are each at least partially made of a thermally conductive material, wherein said thermally conductive material is any of a group comprising: metals, plastics, such as Acrylonitrile butadiene styrene (ABS) , Polycarbonates (PC) or Polyamides (PA), or graphite foil.

In one aspect of the present application the objectives above are achieved by providing a housing arranged to be used in a cooling arrangement as described above.

In one embodiment said housing is a frame. This enables a lower weight through added load-bearing structure.

In one embodiment said housing is a Printed Wiring Board. This enables the cooling arrangement to be implemented without surplus construction details thereby leading to a light-weight and narrow or slim design that is cheaper to manufacture.

In one aspect of the present application the objectives above are achieved by providing a device having a cooling arrangement or housing as described above, which enables a device to benefit from the improved cooling and protection disclosed in the present application.

In one embodiment said device is a mobile terminal. Due to the varying environments a mobile terminal is used in, a mobile terminal benefits from the improved cooling and protection disclosed herein.

In one aspect of the present application the objectives above are achieved by providing a method for cooling a component enclosed in a first portion of a housing, said method comprising shielding (710) said component (401, 404, 406) with a partitioning wall, transferring (720) heat generated by said component to said second housing portion (400b) , establishing (730) an airflow through said second housing portion (400b), and dissipating (740) said heat into said airflow (416, 418) .

As for the cooling arrangement above such a method has the advantage of enabling cooling of components without subjecting them to increased risks of corrosion or other impurities leading to premature failure.

In one embodiment said airflow is established passively. This has the advantage of enabling a cooling arrangement utilising such a method to run without power consumption and to be made smaller.

In one embodiment said airflow is a forced air flow established actively through use of an air actuator. This increases the amount of air that is used to absorb the heat being dissipated which increases the cooling effect.

In one embodiment the method further comprises controlling said air actuator according to a criterion taken from a group comprising: component use, component temperature, system use and system temperature. This enables the cooing to be run at specific intervals and this enables the sound level to be controlled as well as the power consumption and other factors.

In one embodiment said at least one component is thermally connected to the second housing portion through a heat conductor. This increases and simplifies the heat transfer from the components to the air flow.

In one embodiment said airflow is established over cooling fins thermally connected to the at least one component. The cooling fins increase the heat exchanging surface and thereby also the cooling effect.

In one embodiment the method further comprises mounting said housing on a printed wire board on which said at least one component is mounted.

In one aspect of the present application the objectives above are achieved by providing a computer readable medium including at least computer program code for controlling a cooling arrangement comprising a housing, comprising a first housing portion arranged to enclose a component capable of generating heat and a second housing portion, comprising an airflow path, said cooling arrangement further comprising a partitioning wall arranged to shield said component in said first housing portion from an airflow through said airflow path in said second housing portion, said computer readable medium comprising software code for activating an air actuator according to component temperature or component use.

This enables quick, efficient and easy control of a cooling process such as described above. In one aspect of the present application the objectives above are achieved by providing an apparatus incorporating and implementing a computer readable medium according to above.

Further objects, features, advantages and properties of a cooling arrangement and a device according to the present application will become apparent from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present description, the embodiments will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Fig. 1 is an overview of a telecommunications system in which a device according to the present application is used according to an embodiment,

Fig. 2 is a plane front view of a device according to an embodiment,

Fig. 3 is a block diagram illustrating the general architecture of a device of Fig. 1 and 2 in accordance with the present application,

Fig. 4 is a view of an embodiment according to the present application,

Fig. 5 is a view of an embodiment according to the present application, Fig. 6a and 6b are views of an embodiment each according to the present application,

Fig 7 is a flow chart describing a cooling process using an arrangement according to the present application, Fig 8 is a flow chart for a control process for a cooling arrangement according to the present application.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following detailed description, an apparatus and a method according to the teachings of the present application in the form of a cooling arrangement for a cellular/mobile phone will be described by the embodiments. It should be noted that although only a mobile phone is described the teachings of this application can also be used in any electronic device and preferably in portable electronic devices such as laptops, PDAs, mobile communication terminals, media players, game consoles, electronic books and notepads and other electronic devices having a relatively high power consumption and thus be in need of cooling.

FIG. 1 illustrates an example of a cellular telecommunications system in which a device using the teachings of the present application may be applied. In the telecommunication system of FIG. 1, various telecommunications services such as cellular voice calls, www/wap browsing, cellular video calls, data calls, facsimile transmissions, music transmissions, still image transmissions, video transmissions, electronic message transmissions and electronic commerce may be performed between a mobile terminal 100 according to the present application and other devices, such as another mobile terminal 106 or a stationary telephone 132. It is to be noted that for different embodiments of the mobile terminal 100 and in different situations, different ones of the telecommunications services referred to above may or may not be available; the invention is not limited to any particular set of services in this respect.

The mobile terminals 100, 106 are connected to a mobile telecommunications network 110 through Radio Frequency,

RF, links 102, 108 via base stations 104, 109. The mobile telecommunications network 110 may be in compliance with any commercially available mobile telecommunications standard, such as GSM, UMTS, D-AMPS, CDMA2000, FOMA and TD-SCDMA.

The mobile telecommunications network 110 is operatively connected to a wide area network 120, which may be Internet or a part thereof. An Internet server 122 has a data storage 124 and is connected to the wide area network 120, as is an Internet client computer 126. The server 122 may host a www/wap server capable of serving www/wap content to the mobile terminal 100.

A public switched telephone network (PSTN) 130 is connected to the mobile telecommunications network 110 in a familiar manner. Various telephone terminals, including the stationary telephone 132, are connected to the PSTN 130.

The mobile terminal 100 is also capable of communicating locally via a local link 101 to one or more local devices 103. The local link can be any type of link with a limited range, such as Bluetooth, a Universal Serial Bus (USB) link, a Wireless Universal Serial Bus (WUSB) link, an IEEE 802.11 wireless local area network link, an RS- 232 serial link, etc. The local devices 103 can for example be various sensors that can communicate measurement values to the mobile terminal 100 over the local link 101.

An embodiment 200 of the mobile terminal 100 is illustrated in more detail in FIG. 2. The mobile terminal

200 comprises a speaker or earphone 202, a microphone

205, a main or first display 203 and a set of keys 204 which may include a keypad 204a of common ITU-T type

(alpha-numerical keypad representing characters "0"-"9", "*" and "#") and certain other keys such as soft keys 204b, 204c and a joystick 211 or other type of navigational input device. The mobile phone may also comprise an extra display, a secondary display further increasing the power consumption. One device having a first and a second display is the Nokia 9210® Communicator®.

The internal component, software and protocol structure of the mobile terminal 200 will now be described with reference to FIG. 3. The mobile terminal has a controller 300 which is responsible for the overall operation of the mobile terminal and is preferably implemented by any commercially available CPU ("Central Processing Unit"), DSP ("Digital Signal Processor") or any other electronic programmable logic device. The controller 300 has associated electronic memory 302 such as RAM memory, ROM memory, EEPROM memory, flash memory, or any combination thereof. The memory 302 is used for various purposes by the controller 300, one of them being for storing data used by and program instructions for various software in the mobile terminal. The software includes a real-time operating system 320, drivers for a man-machine interface (MMI) 334, an application handler 332 as well as various applications. The applications can include a calendar application 350, a notepad application 360, as well as various other applications 370, such as applications for voice calling, video calling, sending and receiving Short Message Service (SMS) messages, Multimedia Message Service (MMS) messages or email, web browsing, an instant messaging application, a phone book application, a calendar application, a control panel application, a camera application, one or more video games, a notepad application, etc.

The MMI 334 also includes one or more hardware controllers, which together with the MMI drivers cooperate with the first display 336/203, the secondary display 340, the keypad 338/204 and a tactile command input detector or tap detector 342 as well as various other I/O devices such as microphone, speaker, vibrator, ringbone generator, LED indicator, etc. As is commonly known, the user may operate the mobile terminal through the man-machine interface thus formed-

The software also includes various modules, protocol stacks, drivers, etc., which are commonly designated as 330 and which provide communication services (such as transport, network and connectivity) for an RF interface 306, and optionally a Bluetooth interface 308 and/or an IrDA interface 310 for local connectivity. The RF interface 306 comprises an internal or external antenna as well as appropriate radio circuitry for establishing and maintaining a wireless link to a base station (e.g. the link 102 and base station 104 in FIG. 1) . As is well known to a man skilled in the art, the radio circuitry comprises a series of analogue and digital electronic components, together forming a radio receiver and transmitter. These components include, band pass filters, amplifiers, mixers, local oscillators, low pass filters, AD/DA converters, etc.

The mobile terminal also has a SIM card 304 and an associated reader. As is commonly known, the SIM card 304 comprises a processor as well as local work and data memory.

Figure 4 show a schematic view of a cooling arrangement according to the present application. A device having a housing 400 and a controller 402, a battery 404 and other electrical components such as a memory 406 is shown. The components are arranged in a first portion 400a of the housing 400. In a second portion 400b of the housing 400, an air actuator 408, in this embodiment a fan, is arranged under an air inlet (not shown) . It should be understood that the air inlet need not be over the fan

408, but can also be arranged under it or at its side.

The first portion 400a is preferably larger than the second portion 400b to allow for more space or surface area for components 402, 404 and 406 to be mounted on.

A wall 410 partitions the two parts 400a and 400b of the housing 400 from each other. This partitioning wall 410 is in this embodiment made of a heat conductive material such as a metal with a relatively high thermal conductivity (aluminium, copper, magnesium and nickel) or similar. A flexible graphite foil arranged on another construction material can also be used. The partitioning wall 410 is thermally connected to any or all of the components 402, 404 and 406. Heat generated by the components 402, 404 and 406 are thereby transferred to the partitioning wall 410 that acts as a heat sink and cools the thermally connected components 402, 404 and 406.

An air path is defined over the partitioning wall 410 so that air forced by the air actuator, or fan 408, flows along or across the partitioning wall 410 and the heat is absorbed by the air being circulated from an inlet (not shown) through the fan and out through an outlet 416 on the other side 400b of the partitioning wall 410.

The partitioning wall 410 isolates the two portions 400a and 400b from each other so that no air from the second portion 400b can be blown into the first portion 400a. Thus, the components are protected or shielded from any impurities, such as dust, particles or humidity in the air being forced through the fan 408 and through the cooling arrangement along the air path. And, an improved cooling is achieved while not exposing the components 402, 404 and 406 or objects to be cooled to impurities and humidity.

The shielding of said components 402, 404, 406 by said partitioning wall 410 is not to be partial as a partial shielding will still allow impurities, especially humidity, to come into contact with the components causing corrosion and premature failure. A complete shielding from the airflow in the airflow path is thus preferred.

In one embodiment the partitioning wall 410 hermetically encloses said components 402, 404 and 406.

It should be understood that the partitioning wall 410 can have any shape, not only straight as shown in the embodiments. In fact a wavy or rounded form will give a larger surface to dissipate heat into the surrounding air from. An important aspect of the shape of the partitioning wall 410 is that it completely shields the components from the air flow.

The partitioning wall 410 can be made of any material having a relatively high thermal conductivity such as metals, and plastics such as Acrylonitrile butadiene styrene (ABS) , Polycarbonates (PC) or Polyamides (PA) .

It should be understood that in some embodiments said partitioning wall 410 may be made of a material that is not heat conductive whereby the heat is transferred through a heat conductor (414) to the second housing portion (400b) where it is dissipated.

The air actuator 408 could also be a blower, a piezo element a vibrating membrane or similar. The air actuator 408 could also be the surrounding wind's natural movement such as natural blowing or the device, including the cooling arrangement, being propelled through the air.

To further improve the cooling effect one or more cooling fins 412, in this embodiment four, are arranged or mounted on a surface of the second portion 400b of the housing 400 to increase the surface used for heat exchange/dissipation and thereby increase the heat dissipation.

These cooling fins 412 can advantageously be connected to the partitioning wall 410 through an integrated heat conductor 414 that conducts heat between the partitioning wall 410 and the cooling fins 412. The integrated heat conductor 414 is also connected to the components 402, 404 and 406 so that heat can be conducted more efficiently from the components 402, 404, 406 to the partitioning wall 410. The integrated heat conductor 414 consists in this embodiment of metal strips 414a-c arranged on the housing connecting the components 402, 404 and 406 with the portioning wall 410 and some 414b and 414c also to the cooling fins 412.

Alternatively, if the partitioning wall 410 is not thermally conductive the heat conductor 414 transfers the heat from the component into the second portion 400b, possibly to the cooling fins 412, for dissipation.

Alternatively or additionally the cooling fins 412 are mounted on the partitioning wall 410.

It should be understood that the cooling fins 412 can be in other shapes than those shown in figure 4 as long as they are in thermal contact with the air being circulated by the fan 408.

The second portion 400b of the housing is basically an empty space or channel through which air is forced by the fan 408. By arranging the cooling fins 412 in certain shapes and either choosing a very silent fan 408, only running the fan 408 at intervals or by using a loud speaker membrane as the air actuator 408, the second portion of the housing 400b could share some space with a loudspeaker 202 of a mobile phone 200. Naturally, if a fan 408 is used the fan 408 needs to be quiet enough or not running so as to not interfere with the sound quality during music or media playing or ongoing calls. It should be noted that a combination of different types of actuators can be used to generate said airflow. In the embodiments above a loud speaker membrane can be used to achieve the air flow when the loud speaker 202 is used and a fan 408 when the loud speaker 202 is not being used.

In one embodiment the air actuator 408 is controlled by special computer code. The computer code can be is stored on a computer readable media and implemented by hard ware as a component or through software executed through the controller 402 and stored in the memory 406. The air actuator control code defines when the air actuator should be run and at what speed depending on the current temperature or cooling needs. The current temperature can be measured through sensors arranged close to the components or by measuring the components performance.

In an embodiment having more than one air actuators 408 the computer code defines when each of the air actuators

408 is to be operated. In the embodiment wherein the second portion 400b is a loudspeaker channel 202 the computer code could be designed to operate the loud speaker membrane (possibly piezo-electrical) 408 only when the loudspeaker 202 is active or in use and a fan

408 when the loudspeaker 202 is not active.

In one embodiment a microphone 205 in a mobile terminal 200 can be designed as a second portion 400b. As sound is detected by and led into the microphone 205 an airflow is caused in or adjacent to the microphone 205. This airflow can be used for cooling purposes and a mobile terminal 200 can thus rely on surrounding sound waves for generating the airflow to be used for cooling. In one embodiment computer code can be arranged to switch between an active air actuator 408 such as a fan and a passive air actuator 408 such as sound waves.

Alternatively the cooling arrangement comprises an additional second portion 400b of the housing 400 for further cooling. The additional second portion 400b can be used to cool additional components or be arranged to operate at different time intervals than the second portion 400b. The two second portions 400b can also be operated simultaneously, passively or forced.

It should be noted that any combination of second parts 400b and air actuators 408 are possible.

In one embodiment in a mobile terminal 200 a cooling arrangement has said second portion 400b arranged with an active air actuator 408 such as a fan, an additional second portion 400b being a loudspeaker 202 and a further additional second portion 400b being a microphone 205. Computer code is designed to switch the active air actuator 408 on and off depending on the operation of the mobile terminal 200.

It should also be noted (as before) that the cooling arrangement can be used without a fan or other active air actuator 408 relying on natural or normal airflow. For example, as the density of the air will lower as it absorbs heat convection will occur and for some cooling purposes this airflow may be sufficient to provide the necessary cooling. The partitioning wall 410 will still protect the components 402, 404 and 406 from humidity or impurities being carried by the naturally or passively moving air into a device having a cooling arrangement according to the present application.

In one embodiment the integrated heat conductor strips 414 are an integral portion of the housing 400 and in one embodiment, the housing 400 is the integrated heat conductor 414. In this embodiment the whole housing 400 or a large extent of it is made of a heat conductive material .

In one embodiment the metal strips of the integrated heat conductor 414 are arranged as further partitioning walls 410 (see also fig 5, 514) which improve the stability of the housing 400 and further improve the thermal connection between the partitioning wall 410 and the components 402, 404 and 406 and thereby also the cooling effect.

Figure 5 show a schematic view of a housing that can be used with a cooling arrangement according to the present application. A housing 500 has a first 500a and a second portion 500b. The first portion 500a is arranged with an integrated heat conductor 514 consisting of a number of walls 514 made of aluminium. The integrated conductor 514 also includes the backbone of the housing 500, i.e. the frame of the housing 500 thereby rendering the housing itself to be the integral heat conductor 514. This ensures that any electrical component mounted on or connected to while being enclosed by the housing 500 is thermally connected to the integrated heat conductor 514.

The second portion 500b is arranged with an air inlet 518, over which a fan (not shown) is to be mounted, and an air outlet 516. The fan 408 is mounted directly over the inlet 518 in one embodiment on said second portion 500b of said housing 500 adjacent the cooling fins 512. It should be understood that the fan 408 can be mounted either on the same surface as the cooling fins 512 rendering a thinner or slimmer over-all design of the cooling arrangement.

Mounting the fan 408 on an opposite surface of said second portion 500b to the surface the cooling fins 412 are mounted on the air flow path renders the airflow to flow more easily along the air flow path thus further improving the cooling effect.

As can be seen in fig 5A the inlet is arranged as a mesh which acts as a filter against solid objects and dust. A number of cooling fins 512, in this embodiment 3, are arranged between the air inlet 518 and the air outlet 516.

Between the two housing parts 500a and 500b is a partitioning wall 510 that separates the two housing parts 500a and 500b from each other and prevents any air to be circulated through the second portion 500b to come into the first portion 500a. The partitioning wall 510 is also made of a heat conductive material, aluminium, and thermally connected to the cooling fins 512 through the integrated heat conductor 514. The partitioning wall 510 and the cooling fins 512 thus acts as a heat sink for the housing and any components mounted therein.

It should be understood that in some embodiments the partitioning wall 510 may be made to be a part of the housing 500 and may also or alternatively be made of a material that is not thermally conductive. It also should be understood that the housing 500 could be a Printed Wiring Board (PWB) .

Figure 6a show a schematic side view of a device having a cooling arrangement according to the present application. A frame or housing 600 is arranged with a Printed Circuit Board (PCB) or Printed Wiring Board (PWB) 620 commonly used to hold electrical components 602, 604 and 606 to form a printed circuit assembly (PCA) . The PWB 620 is arranged opposite the frame so that they can be mounted together or assembled as indicated by the dashed lines. The PWB 620 carries or holds a processor 602, a memory 606 and a battery 604. It should be understood that the PWB 620 also carries other electrical components that are not shown for the sake of clarity. A fan 608 is also mounted on the PWB 620.

The frame or housing 600 has a first 600a and a second portion 600b. The first portion 600a is so dimensioned as to fit with the PWB 620 and house the components 602, 604 and 606 mounted on the PWB 620 when the housing is assembled on the PWB 620. The frame is made of heat conducting material and thus constitutes an integrated heat conductor 614. A partitioning wall 610 separates the first housing portion 600a from the second housing portion 600b. The second portion 600b of the housing has a number of cooling fins 612, in this embodiment three, that are thermally connected to the integrated heat conductor 614. When the PWB 620 is mounted on the frame or housing 600 the fan 608 is arranged adjacent the cooling fins 612 in the second portion 600b. As the fan 608 is activated it will circulate or force air through an inlet (not shown) over the cooling fins 612, along the partitioning wall 610 and also the integrated heat conductor 614 and out through an outlet (not shown) . The fan 608 and the cooling fins 612 together with the partitioning wall 610 thus forms a fan powered heat sink for efficient cooling of the integrated heat conductor 614 and any component 602, 604 and 606 connected to the integrated heat conductor 614.

The partitioning wall 610 has an extent going from one end of the frame 500 to the other end and from the housing to the PWB 620, when they are mounted, thereby effectively separating the two parts 600a and 600b and preventing any air from flowing from the second portion

600b into the first portion 600a. Thus, the components housed in the first portion 600a are protected from any impurities and humidity in the flowing air in being circulated in the second portion 600b.

It should be understood that the housing 600 and the PWB 620 could be integrated into the same housing or frame.

A mobile phone such as Nokia 3210™ comprises a front cover and a back cover and in between these two a frame on which most of the components are mounted. The housing 400, 500, 600 described above (and below) can advantageously be used as such a frame for a mobile phone .

Figure 6b show a schematic side view of a device having a cooling arrangement according to the present application. The arrangement in figure 6b is similar to the one described with reference to figure 6a. One differentiating feature is the positioning of the air actuator or fan 608. In figure 6b the fan 608 is arranged on the second portion 600b of the housing or frame 600 under an inlet (not shown) . The arrangement of figure 6b is adapted to be mounted on an existing PWB 620 and can thus be installed in already existing devices for providing an improved cooling.

It should be noted that in fig 6b the housing 600 is wider than the PWB 620 with the second portion 600b extending past the PWB 620. the heat is thereby transferred away from the first portion 600a and the PWB 620 by the heat conductor 614 and this enables the cooling arrangement to be mounted on PWBs 620 that are located in narrow spaces. Also, as a sufficient air flow can sometimes be difficult to achieve in a narrow or poorly vented spaces, it is beneficial to lead the heat away from these spaces to areas where it is easier to achieve a sufficient air flow.

Figure 7 show a flow chart for a method or a cooling process using a cooling arrangement as above. In a first step 710 components that are to be cooled are shielded by a partitioning wall and in a second step 720 heat generated by the components is transferred through a thermal connection, such as a heat conductor, to a partitioning wall. An airflow is established, passively, forcedly or both along the partitioning wall in a step 730 and the components are shielded from this airflow by the partitioning wall as in step 710 and thus protected from any impurities being carried in the airflow. In a step 740 the transferred heat is dissipated into the airflow thus effecting cooling of the components, whereby the partitioning wall functions as a heat sink for the components at the same time as it protects them from impurities thereby preventing corrosion and premature failure .

Figure 8 show a flow chart for controlling a cooling process using a cooling arrangement as above. In a first step 810 an operating status is detected. This operating status can be a component temperature, a component use or a mode of operation of the device for which the cooling arrangement is used. The status can be measured using sensors, such as temperature sensors or by polling information from a device controller (402 in fig 4) . In a second step the status is matched against certain criteria 820. These criteria depend on the operating status being detected and can be a threshold temperature, a threshold activity level or a set of operating modes necessitating special care. If any of the criteria is met an air actuator is activated in a further step 830. After the air actuator has been activated or if none of the criteria are met a new status is detected in step 810. Step 810 can be repeated continuously or at certain intervals depending on the implementation. Step 810 can also be initiated specifically by a process.

It should be understood that the criteria can also be negative which in practise leads to an air activator being inactivated when any of the criteria are met.

An example is when a mobile terminal, which will be described with simultaneous reference to figs 2 and 4, is arranged with a cooling arrangement as described above having an active air actuator 408 in the form of a fan. A second portion 400b of a housing 400 is arranged as a loudspeaker 202. A user being connected to the internet through a GPRS connection, as explained above with reference to figure 1 and 3, is downloading an application. While this operation is performed a temperature rise is detected (810) in an RF interface component used for the connection (306 in fig 3) . The fan 408 is activated to increase the heat dissipation from the component 306 as explained above. During the ongoing download an incoming call is received by the mobile terminal 200 and accepted by the user. The loud speaker 202 is activated to play the voice of the caller during the call. To enable the best possible sound quality the fan 408 is turned off so as not to disturb and the cooling arrangement will rely on the sound waves generated by the loudspeaker 202, operating as an air actuator 408, to provide the airflow along with natural air movement such as that caused by convection. When the call is ended this is again detected by the controller 402 in step 810), a new criterion is met (step 820) and the fan 408 is activated (step 830) .

In one embodiment a special criterion is checked to see if a headset is connected to the terminal 200. If no such headset is detected the loud speaker 205 will be used for the call and the loudspeaker 205 will act as the air actuator. If a headset is detected the fan 408 will be kept active as the sound will be directed through the headset thereby leaving the sound quality unaffected by the fan operation.

A cooling arrangement, such as any of the above, thus provide the advantages of protecting the components housed therein while still maintaining an efficient cooling of them and it also increases the stability of the housing through the integrated heat conductor and making it easy to install. A cooling arrangement such as above can beneficially be used to cool more than one component. The rate of cooling needed for each component can be determined through the choice of the integrated heat conductor and how it is connected to the component to be cooled. Using heat conductors of different conductivity, either through different physical dimensions or properties, the relative cooling in respect to the total cooling achieved for each component can be controlled or pre-determined. An arrangement such as this allows a designer to control the heat dissipation of a device so that more critical components get the cooling needed for efficient operation.

Although the teaching of the present application has been described in detail for purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the scope of the teaching of this application.

For example, although the teaching of the present application has been described in terms of a cooling arrangement for a mobile phone, it should be appreciated that the invention may also be applied to other types of electronic devices, such as music players, palmtop computers and the like. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the teachings of the present application .

The term "comprising" as used in the claims does not exclude other elements or steps. The term "a" or "an" as used in the claims does not exclude a plurality. A unit or other means may fulfil the functions of several units or means recited in the claims.

Claims

CLAIMS :

1. A cooling arrangement comprising a housing (400), said housing (400) comprising

a first housing portion (400a) , arranged to enclose at least one component (402, 404, 406) capable of generating heat, and

a second housing portion (400b), comprising an air flow path (416, 418),

and wherein said at least one component (402, 404, 406) being thermally connected to said second housing portion (400b) , and

said at least one component (402, 404, 406) being shielded from air flowing along said air flow path (416, 418) for protecting said component (402, 404, 406) from impurities being carried by said air flow.

2. A cooling arrangement according to claim 1 further comprising a partitioning wall (410) for separating the air content of said first (400a) and second (400b) housing portions.

3. A cooling arrangement according to claim 2, wherein said partitioning wall (410) is arranged to dissipate said generated heat from said component (402, 404, 406) into said air flow path (416, 418) .

4. A cooling arrangement according to any of claims 1 to 3, further comprising a heat conductor (414) for transferring said generated heat from said at least one component (402, 404, 406) to said second housing portion (400b) for dissipation into said air flow.

5. A cooling arrangement according to claim 4, wherein said heat conductor (414) is an integral part of at least one of walls that define said first housing portion (400a) and an integral part of at least one of walls defining said second housing portion (400b) .

6. A cooling arrangement according to claim 4, wherein said partitioning wall (410) is an integral part of said heat conductor (414) or is thermally connected to said heat conductor (414).

7. A cooling arrangement according to claim 2, wherein said partitioning wall (410) is said heat conductor (414) .

8. A cooling arrangement according to claim 1 further comprising an air actuator (408) for forcing said air flow along said air flow path.

9. A cooling arrangement according to claim 8, wherein said air actuator is one from the group consisting of: a fan, a blower, a piezo element, a loud speaker membrane and a vibrating element.

10. A cooling arrangement according to claim 1 further comprising an inlet (416) and an outlet (418) arranged to define said air flow.

11. A cooling arrangement according to claim 1 further comprising cooling fins (412) arranged in said air flow path (416, 418) being thermally connected to said heat conductor (414), wherein said cooling fins (412) are arranged to support said dissipation of said heat.

12. A cooling arrangement according to claim 1, wherein said housing (600) being further arranged to be connected to a printed wire board (620) on which said at least one component (602, 604, 606) is mounted, wherein said first housing portion (600a) is arranged to enclose said component (602, 604, 606) upon connection of said housing (600) to said printed wire board (620) .

13. A cooling arrangement according to claim 2 or 4 or 11, wherein said partitioning wall (410), said heat conductor (414) and/or said cooling fins (412) are each at least partially made of a thermally conductive material, wherein said thermally conductive material is any of a group comprising: metals, plastics or graphite foil.

14. A cooling arrangement comprising a housing (400), said housing (400) comprising

a first housing portion (400a) , arranged to enclose at least one component (402, 404, 406) capable of generating heat and

a second housing portion (400b) comprising an air flow path (416, 418), and

wherein said cooling arrangement comprises means for thermally connecting at least one component (402, 404, 406) to said second housing portion (400b), and means for shielding said at least one component (402, 404, 406) from air flowing along said air flow path (416, 418) for protecting said component (402, 404, 406) from impurities being carried by said air flow.

15. A cooling arrangement according to claim 14 further comprising partitioning means (410) for separating the air content of said first (400a) and second (400b) housing portions.

16. A cooling arrangement according to claim 15, wherein said partitioning means (410) are arranged to dissipate said generated heat from said component (402, 404, 406) into said air flow path (416, 418) .

17. A cooling arrangement according to any of claims 14 to 16 further comprising heat conductor means for transferring said generated heat from said at least one component to said second housing portion for dissipation into said air flow.

18. A cooling arrangement according to claim 17, wherein said heat conductor means (414) is an integral part of at least one of the walls that define said first housing portion (400a) and an integral part of at least one of the walls defining said second housing portion (400b) .

19. A cooling arrangement according to claim 17, wherein said partitioning means (410) is an integral part of said heat conductor means (414) or is thermally connected to said heat conductor means (414) .

20. A cooling arrangement according to claim 15, wherein said partitioning means (410) is said heat conductor means (414) .

21. A cooling arrangement according to claim 14 further comprising air actuator means (408) for forcing said air flow along said air flow path.

22. A cooling arrangement according to claim 21, wherein said air actuator means is one from the group consisting of: a fan, a blower, a piezo element, a loud speaker membrane and a vibrating element.

23. A cooling arrangement according to claim 14 further comprising an inlet (416) and an outlet (418) arranged to define said air flow path.

24. A cooling arrangement according to claim 14 further comprising cooling fins (412) arranged in said air flow path (416, 418) being thermally connected to said heat conductor means (414), wherein said cooling fins (412) are arranged to support said dissipation of said heat.

25. A cooling arrangement according to claim 14, wherein said housing (600) further comprises means for being connected to a printed wire board (620) on which said at least one component (602, 604, 606) is mounted, wherein said first housing portion (600a) is arranged to enclose said component (602, 604, 606) upon connection of said housing (600) to said printed wire board (620) .

26. A cooling arrangement according to claim 15 or 17 or 24, wherein said partitioning wall (410), said heat conductor (414) and/or said cooling fins (412) are each at least partially made of a thermally conductive material, wherein said thermally conductive material is any of a group comprising: metals, plastics or graphite foil.

27. A housing arranged to be used in a cooling arrangement as in any preceding claim.

28 A housing as in claim 27, wherein said housing is a frame.

29 A housing as in claim 27, wherein said housing is a Printed Wiring Board.

30. A device having a cooling arrangement or housing as in any preceding claim.

31. A device as in claim 30, wherein said device is a mobile terminal.

32. A method for cooling a component (402, 404, 406) enclosed in a first portion (400a) of a housing (400), said method comprising:

shielding (710) said component (402, 404, 406) with a partitioning wall,

transferring (720) heat generated by said component to said second housing portion (400b),

establishing (730) an airflow through said second housing portion (400b) , and

dissipating (740) said heat into said airflow (416, 418) .

33. A method according to claim 32 wherein said airflow is established passively.

34. A method according to claim 32 wherein said airflow is a forced air flow established actively through use of an air actuator.

35. A method according to claim 34 further comprising controlling said air actuator according to a criterion taken from a group comprising: component use, component temperature, system temperature and system use.

36. A method according to claim 32 wherein said at least one component (402, 404, 406) is thermally connected to said second housing portion through a heat conductor (414) .

37. A method according to claim 32 wherein said airflow is established over cooling fins thermally connected to said at least one component (402, 404, 406) .

38. A method according to claim 32 further comprising mounting said housing (600) on a printed wire board (620) on which said at least one component (602, 604, 606) is mounted.

39. A computer readable medium including at least computer program code for controlling a cooling arrangement comprising a housing (400), comprising a first housing portion (400a) arranged to enclose a component (402, 404, 406) capable of generating heat and a second housing portion (400b), comprising an airflow path (416, 418), said cooling arrangement further comprising a partitioning wall (410) arranged to shield said component (402, 404, 406) in said first housing portion (400a) from an airflow through said airflow path in said second housing portion (400b) , said computer readable medium comprising software code for activating an air actuator (408) according to component temperature or component (402, 404, 406) use.

40. An apparatus incorporating and implementing a computer readable medium according to claim 39.