This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2007-145454, filed May 31, 2007, the entire contents of which are incorporated herein by reference.
1. Field
One embodiment of the invention relates to a technology for cooling an exothermic component mounted on a circuit board.
2. Description of the Related Art
An electronic apparatus such as a portable computer is equipped with a circuit board on which an exothermic component is mounted. In order to cool the exothermic component, various types of cooling units are provided in electronic apparatuses.
In Jpn. Pat. Appln. KOKAI Publication No. 9-232488, a cooling structure for cooling a CPU mounted on a circuit board is disclosed. In this cooling structure, a first heat transfer plate and an auxiliary heat pipe are provided on a surface of surfaces of the circuit board on which a CPU is mounted so that heat can be transferred from the CPU to the plate and the auxiliary heat pipe. On a surface of the circuit board on which the CPU is not mounted, a second heat transfer plate and a heat-collecting heat pipe are provided so that heat can be transferred from the CPU to the second heat transfer plate and the heat-collecting heat pipe through pins penetrating the circuit board. A heat radiating heat pipe is provided at a position which is between the auxiliary heat pipe and the heat collecting heat pipe, and at which the circuit board is not present. This heat radiating heat pipe is configured so that it can receive heat from the auxiliary heat pipe and the heat collecting heat pipe.
Incidentally, the above-mentioned cooling structure is relatively large and thick as a whole. Further, the inventor of the present invention has found that by the use of the above-mentioned cooling structure, there is the possibility of part of the cooling structure being not effectively utilized if a heat transfer amount on the side of the circuit board on which the CPU is mounted and a heat transfer amount on the side on which the CPU is not mounted are different from each other.
A general architecture that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.
Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, an electronic apparatus is provided with a casing; a circuit board which is contained in the casing, and on which an exothermic component is mounted; a first heat receiving plate opposed to one side of the circuit board and the exothermic component, and thermally connected to the exothermic component; a second heat receiving plate opposed to another side of the circuit board; a heat radiating section provided in the casing; and a heat transfer member provided with a heat receiving end portion thermally connected to at least one of the first and second heat receiving plates, and a heat radiating end portion thermally connected to the heat radiating section. The first and second heat receiving plates each extend to a region outside the circuit board, and are joined to each other in the region outside the circuit board so as to be thermally connected to each other. The heat receiving end portion of the heat transfer member is located in a line to the circuit board along a direction parallel with a surface of the circuit board.
According to one embodiment of the invention, a cooling unit is provided with a first heat receiving plate which is to be opposed to one side of a circuit board and an exothermic component mounted on the circuit board, and to be thermally connected to the exothermic component; a second heat receiving plate which is to be opposed to another side of the circuit board; and a heat transfer member provided with a heat receiving end portion which is thermally connected to at least one of the first and second heat receiving plates, and a heat radiating end portion which is to be thermally connected to a heat radiating section. The first and the second heat receiving plates each extend to a region outside the circuit board, and are joined to each other in the region outside the circuit board so as to be thermally connected to each other. The heat receiving end portion of the heat transfer member is to be located in a line to the circuit board along a direction parallel with a surface of the circuit board.
Embodiments of the present invention will be described below on the basis of drawings showing examples in which the embodiments are applied to portable computers.
The casing 4 includes an upper wall 4a, a peripheral wall 4b, and a lower wall 4c. Exhaust ports 6 are opened in the peripheral wall 4b. As shown in
As shown in
The display unit 3 is supported on a rear end part of the casing 4 through a pair of hinge sections (not shown). As a result, the display unit 3 is rotatable between a closed position, at which the display unit 3 is laid down so as to cover the upper wall 4a from above, and an opened position, at which the display unit 3 is raised so as to expose the upper wall 4a.
As shown in
The internal module 16 is provided with a circuit board 21 serving as a sub-board, and exothermic components 22 and 23 mounted on the circuit board 21. An example of the exothermic component 22 or 23 is a memory chip of a memory module. As shown in
As shown in
The heat sink 24 is an example of a heat radiating section. The heat sink 24 is formed by arranging a plurality of plate-like fins, and is opposed to the exhaust ports 6 of the casing 4. The cooling fan 25 intakes air inside the casing 4, and blows the air toward the heat sink 24 so as to cool the heat sink 24.
Incidentally, in this embodiment, the heat sink 24 and the dedicated cooling fan 25 for cooling the heat sink 24 are provided. Instead, the cooling fan 25 may be omitted, and a heat sink provided with, e.g., pin-like projections, and cooled by a flow of air generated by driving of a cooling fan for cooling, e.g., a CPU may be provided as a heat radiating section.
As shown in
As shown in
The second heat receiving plate 32 is opposed to the circuit board 21 from the opposite side of the first heat receiving plate 31, and the internal module 16 is interposed between the plate 32 and the first heat receiving plate 31. That is, the second heat receiving plate 32 is opposed to the second surface 21b (i.e., another side) of the circuit board 21 on which the second exothermic components 23 are mounted, and is thermally connected to the second exothermic components 23. Between the second heat receiving plate 32 and the second exothermic components 23, for example, a thermal conducting member 35 is interposed, thereby enhancing the thermal connection between the second heat receiving plate 32 and the second exothermic components 22.
As shown in
The first and second heat receiving plates 31 and 32 joined to each other form, for example, a heat receiving member 37 with a U-shaped form. The first and second heat receiving plates 31 and 32 according to this embodiment are formed integral with each other by bending, for example, a plate member.
Accordingly, in other words, the heat receiving member 37 constituted of one plate member forms, by being bent, the first and second heat receiving plates 31 and 32 between which the circuit board 21 is interposed. Incidentally, in this embodiment, a center of the bent part of the heat receiving member 37 is defined as the border between the first heat receiving plate 31 and the second heat receiving plate 32.
As shown in
The first and second heat receiving plates 31 and 32 may be fixed to the internal module 16 by forming the heat receiving member 37 by using an elastic material, and inserting the internal module 16 into the two heat receiving plates 31 and 32. Alternatively, at least one of the first and second heat receiving plates 31 and 32 may be fixed to the internal module 16 by screwing. Instead, the thermal conducting members 35 interposed between the heat receiving plates 31 and 32 and the exothermic components 22 and 23 may be given adhesion, and the heat receiving plates 31 and 32 may be fixed to the internal 16 by means of the thermal conducting members 35.
The heat receiving member 37 is standardized so as to allow it to be compatible with, for example, both a type of circuit board in which exothermic components are mounted on both sides, and a type of circuit board in which an exothermic component or exothermic components is/are mounted only on one side. The heat receiving member 37 can also be applied to a circuit board 21 in which an exothermic component or exothermic components is/are mounted only on one side as shown in
As shown in
As shown in
It is sufficient if the heat receiving end portion 33a of the heat transfer member 33 is thermally connected to at least one of the first and second heat receiving plates 31 and 32. The first and second heat receiving plates 31 and 32 are thermally connected to each other, and hence if the heat transfer member 33 is thermally connected to at least one of the first and second heat receiving plates 31 and 32, the heat transfer member 33 can receive heat from both the first and second heat receiving plates 31 and 32.
As shown in
That is, the heat receiving end portion 33a of the heat transfer member 33 is disposed in the inside region S formed between the first and second heat receiving plates 31 and 32. In other words, the heat receiving end portion 33a of the heat transfer member 33 is interposed between the first and second heat receiving plates 31 and 32 together with the internal module 16.
Further, from another point of view, the first heat receiving plate 31 includes a first surface 31a opposed to the circuit board 21, and a second surface 31b formed on the opposite side of the first surface 31a. The second heat receiving plate 32 includes a third surface 32a opposed to the circuit board 21, and a fourth surface 32b formed on the opposite side of the third surface 32a. When the heat transfer member 33 is viewed from a direction parallel with the surface 21a of the circuit board 21, the heat receiving end portion 33a of the heat transfer member 33 is arranged between the second surface 31b and the fourth surface 32b. That is, the heat receiving end portion 33a of the heat transfer member 33 is arranged within the height H (i.e., component height H, i.e., mounting height H) of the heat receiving member 37.
As shown in
The method for joining the heat transfer member 33 to the heat receiving member 37 is not particularly limited, and the joining is performed by using, for example, solder 51 or a thermally-conductive adhesive. Specific examples of the thermally-conductive adhesive are a heat setting epoxy adhesive, a one-component epoxy adhesive or a two-component epoxy adhesive, and the like.
Next, the function of the portable computer 1 will be described below.
When the portable computer 1 is used, the first and second exothermic components 22 and 23 generate heat. A large amount of the heat generated by the first exothermic components 22 is received by the first heat receiving plate 31, and is conducted to the heat receiving end portion 33a of the heat transfer member 33 through the first heat receiving plate 31. A large amount of the heat generated by the second exothermic components 23 is received by the second heat receiving plate 32, and is conducted to the heat receiving end portion 33a of the heat transfer member 33 through the first and second heat receiving plates 31 and 32.
The heat transfer member 33 transfers the heat received by the heat receiving end portion 33a to the heat radiating end portion 33b, and conducts the transferred heat to the heat sink 24. The heat conducted to the heat sink 24 is exhausted to the outside of the casing 4 by the cooling of the heat sink 24 by means of the cooling fan 25.
With the cooling unit 26 configured as described above, it is possible to realize a higher cooling capability as compared with a case where the first and second heat receiving plates 31 and 32 are separately provided, and are connected to the heat receiving end portion 33a of the heat transfer member 33 independently of each other.
If it is temporarily assumed that the first and second heat receiving plates 31 and 32 are separately provided, and are connected to the heat receiving end portion 33a of the heat transfer member 33 independently of each other, heat is hardly transferred from/to the first heat receiving plate 31 to/from the second heat receiving plate 32. That is, if the heat receiving end portion 33a lies between the first heat receiving plate 31 and the second heat receiving plate 32, the first heat receiving plate 31 functions as a member for conducting the heat generated from the first exothermic components 22 to the heat transfer member 33, and the second heat receiving plate 32 functions as a member for conducting the heat generated from the second exothermic components 23 to the heat transfer member 33, and such functions are practically independent of each other.
For example, in a case where the heating value of the first exothermic components 22 and that of the second exothermic components 23 are different from each other, one of the first and second heat receiving plates 31 and 32 becomes higher in temperature than the other in some cases. If the first and second heat receiving plates 31 and 32 function independently of each other even in such a case, it can be said that the heat receiving plate which becomes relatively higher in temperature is more effective as a heat radiating member. However, the heat receiving plate which becomes relatively lower in temperature is in a state where still some redundant capacity is left unused, as a heat radiating member, or in some cases, the heat receiving plate may be in a state where it is not effectively used.
On the other hand, in the cooling unit 26 according to this embodiment, the first and second heat receiving plates 31 and 32 are connected to each other, and heat can be transferred from/to one of them to/from the other of them. Accordingly, when one of the first and second heat receiving plate 31 and 32 becomes higher in temperature than the other, heat is transferred from the heat receiving plate which becomes relatively higher in temperature to the heat receiving plate which becomes relatively lower in temperature, thereby causing the heat receiving plate that becomes relatively lower in temperature to function as a heat sink which assists the other heat receiving plate that becomes relatively higher in temperature in radiating heat. As described above, the cooling unit 26 can realize a high cooling capability.
For example, in a case where the cooling unit 26 is applied to a circuit board in which an exothermic component is mounted only on the first surface 21a, the second heat receiving plate 32 is not brought into an idle state, and functions as a heat sink for assisting the first heat receiving plate 31 in radiating heat. With a cooling unit 26 standardized so as to allow it to be compatible with both a circuit board in which exothermic components are mounted on both sides, and a circuit board in which exothermic components are mounted only on one side, as described above, further utility may be exhibited easily.
Further, with the cooling unit 26, a reduction in thickness of the cooling structure can be realized. For example, if the heat transfer member 33 is joined to the first or second heat receiving plate 31 or 32 in the region in which the first and second heat receiving plates 31 and 32, and the circuit board 21 overlap with each other, the cooling structure becomes thick as a whole. In contrast, by locating the heat receiving end portion 33a of the heat transfer member 33 in a line to the circuit board 21 along the direction parallel with the surface 21a of the circuit board 21, it is possible to avoid a situation in which the heat transfer member 33 overlaps the circuit board 21 in the direction in which the circuit board 21 and the heat receiving plates 31 and 32 overlap each other. This enables reduction in thickness of the cooling structure.
Furthermore, in order that the first and second heat receiving plates 31 and 32 may be thermally connected to each other, the plates 31 and 32 extend to a region outside the circuit board 21, and are connected to each other in the region outside the circuit board 21. In this embodiment, the heat receiving end portion 33a of the heat transfer member 33 is joined to the first heat receiving plate 31 at a part thereof in the region which is located outside the circuit board 21 and to which the first heat receiving plate 31 extends. By effectively utilizing such parts of the first and second heat receiving plates 31 and 32 in the region which is located outside the circuit board, and to which the plates 31 and 32 extend, it is easily possible to locate the heat receiving end portion 33a of the heat transfer member 33 in a line to the circuit board 21 along the direction parallel with the surface 21a of the circuit board 21.
In a case where the heat receiving end portion 33a of the heat transfer member 33 is arranged within the height H of the heat receiving member 37, members around the internal module 16 excluding the heat sink 24 and the cooling fan 25 can be kept within the height H of the heat receiving member 37, and hence the cooling structure becomes thinner.
The heat receiving end portion 33a of the heat transfer member 33 may be joined to the heat receiving member 37 from, for example, the opposite side of the circuit board 21 in the direction parallel with the surface 21a of the circuit board 21 (see
In a case where the heat transfer member 33 may be arranged in the vicinity of the circuit board 21, it is possible to shorten the length of the heat transfer path between the heat receiving end portion 33a of the heat transfer member 33 and the exothermic components 22 and 23. This enables the cooling unit 26 to realize a further higher cooling capability. Further, in a case where the heat receiving end portion 33a is provided between the heat receiving member 37 and the circuit board 21, it is possible to join the heat receiving end portion 33a to the flat part 45 of the first heat receiving plate 31 in the region which is located outside the circuit board 21, and to which the heat receiving plate 31 extends. The surface of the flat part 45 is flat, and hence the heat receiving end portion 33a may be stably joined to the flat part 45.
In a case where the part 57 of the heat receiving member 37 located outside the circuit board 21 is formed into an arcuate shape, a dead space is liable to appear between the heat receiving member 37 and the circuit board 21.
It can be said that disposing the heat receiving end portion 33a of the heat transfer member 33 between the heat receiving member 37 and the circuit board 21 is arranging the heat transfer member 33 by effectively utilizing the region liable to be a dead space. In a case where the part 57 of the heat receiving member 37 outside the circuit board 21 is formed into an arcuate shape, and the heat transfer member 33 is joined to an inner surface 37a of the heat receiving member 37, joining of the heat transfer member 33 may be performed more stably as compared with a case where the heat transfer member 33 is joined to an outer surface 37b of the heat receiving member 37 (see
In a case where the first and second heat receiving plates 31 and 32 are formed integral with each other by bending a plate material, it is easily possible to obtain the first and second heat receiving plates 31 and 32 between which the circuit board 21 is interposed. That is, it is possible to reduce the number of components constituting the cooling structure, and easily form the first and second heat receiving plates 31 and 32 without a complicated shape.
In a case where the second exothermic components 23 are mounted on the second surface 21b of the circuit board 21, and the second heat receiving plate 32 is thermally connected to the second exothermic components 23, heat generated from the second exothermic components 23 is conducted to the heat receiving end portion 33a of the heat transfer member 33 through the heat receiving plate 32. This can promote cooling of the second exothermic components 23.
By inserting the packing member 43 for filling the gap between the circuit board 21 and the second heat receiving plate 32 in a case where no exothermic component is mounted on the second surface 21b of the circuit board 21, it is possible to also apply a heat receiving member 37 standardized in accordance with a circuit board 21 in which exothermic components are mounted on both surfaces to a circuit board 21 in which an exothermic component is mounted only on one surface.
In a case where the first and second heat receiving plates 31 and 32 are opposed to a region of the circuit board 21 outside the connecting end section 41, it is possible to reliably insert the connecting end section 41 of the circuit board 21 into the socket 15 even in a state where the heat receiving member 37 is attached to the internal module 16.
Next, various modification examples of the cooling unit 26 will be described below with reference to
With the cooling unit 26 configured as described above too, for the same reason as described previously, a high cooling capability can be realized, and reduction in thickness of the cooling structure may be realized. With this modification, the assembling facility of the cooling unit 26 may be further improved. That is, as for the cooling unit 26, after holding the heat transfer member 33 and the circuit board 21 between the first and second heat receiving plates 31 and 32, the first and second heat receiving plates 31 and 32 can be joined to each other. This improves the workability at the time of containing the heat transfer member 33 and the circuit board 21 in the space between the first and second heat receiving plates 31 and 32.
Incidentally, these first and second modifications are not limited to the cooling unit 26 according to the first embodiment, and may also be appropriately applied to the embodiments to be described below.
Next, a portable computer 1 as an electronic apparatus according to a second embodiment of the present invention will be described below with reference to
As shown in
The fastening support 61 holds a first heat receiving plate 31, an internal module 16, and a second heat receiving plate 32 between the first end part 63 and the second end part 64. The first end part 63 presses the first heat receiving plate 31 against first exothermic components 22. The second end part 64 presses the second heat receiving plate 32 against second exothermic components 23.
As a result of this, thermal connection between each of the heat receiving plates 31 and 32 and each of the exothermic components 22 and 23 is enhanced, and the first and second heat receiving plates 31 and 32 are fixed to the internal module 16. Providing such fastening supports 61 makes the elasticity of the heat receiving member 37 unnecessary, and makes the screws or the adhesive for fixing the first and second heat receiving plates 31 and 32 to the internal module 16 unnecessary.
As shown in
With such a cooling unit 26, like in the first embodiment, a high cooling capability may be realized, and reduction in thickness of the cooling structure may be realized. Furthermore, in a case where the heat receiving plates 31 and 32 are pressed against the exothermic components 22 and 23, respectively by the fastening supports 61, thermal connection between each of the heat receiving plates 31 and 32 and each of the exothermic components 22 and 23 is enhanced, and a further higher cooling capability may be realized.
Next, a portable computer 1 as an electronic apparatus according to a third embodiment of the present invention will be described below with reference to
As shown in
When the lid 8 is attached to a lower wall 4c, the first auxiliary member 71 is compressed between the main circuit board 14 and the first heat receiving plate 31, and the second auxiliary member 72 is compressed between the lid 8 and the second heat receiving plate 32. As a result of this, the first auxiliary member 71 presses the first heat receiving plate 31 against first exothermic components 22. The second auxiliary member 72 presses the second heat receiving plate 32 against second exothermic components 23.
With such a cooling unit 26, like the first embodiment, a high cooling capability may be realized, and reduction in thickness of the cooling structure may be realized. Further, in a case where the heat receiving plates 31 and 32 are pressed against the exothermic components 22 and 23 by the first and second auxiliary members 71 and 72, thermal connection between each of the heat receiving plates 31 and 32 and each of the exothermic components 22 and 23 is enhanced, and a further higher cooling capability may be realized.
Next, a portable computer 1 as an electronic apparatus according to a fourth embodiment of the present invention will be described below with reference to
As shown in
As a result of this, the heat receiving plates 31 and 32 are rotatably coupled to the heat transfer member 33. The cut-off sections 82 of the first heat receiving plate 31 are provided in regions opposed to the coupling sections 81 of the second heat receiving plate 32, respectively. The cut-off sections 82 of the second heat receiving plate 32 are provided in regions opposed to the coupling sections 81 of the first heat receiving plate 31, respectively. The first and second heat receiving plates 31 and 32 cooperate with each other in forming a hinge structure a hinge axis of which is the heat receiving end portion 33a of the heat transfer member 33.
Incidentally, it is sufficient if at least one of the first and second heat receiving plates 31 and 32 is rotatable on the heat receiving end portion 33a. Incidentally, for example, at least one of the side sections 81a of the coupling section 81 of the first heat receiving plate 31 is in contact with a side section 81a of the coupling section 81 of the second heat receiving plate 32. As a result of this, the first and second heat receiving plates 31 and 32 according to this embodiment are also coupled to each other, and are thermally connected to each other.
As shown in
With such a cooling unit 26, like the first embodiment, a high cooling capability may be realized, and reduction in thickness of the cooling structure may be realized. Further, if the second heat receiving plate 32 is relatively rotatable with respect to the first heat receiving plate 31, the user may fit the internal module 16 into the heat receiving member 37 more easily. In a case where the first and second heat receiving plates 31 and 32 form a hinge structure a hinge axis of which is the heat receiving end portion 33a, it is possible to make the second heat receiving plate 32 rotatable with respect to the first heat receiving plate 31 by a simple structure without providing any other constituent members.
Next, a portable computer 1 as an electronic apparatus according to a fifth embodiment of the present invention will be described below with reference to
As shown in
With such a cooling unit 26, for the same reason as the first embodiment, a high cooling capability may be realized, and reduction in thickness of the cooling structure may be realized. In a case where the heat receiving end portion 33a of the heat transfer member 33 is arranged within the height H of the heat receiving member 37, members around the internal module 16, excluding the heat sink 24 and the cooling fan 25, may be kept within the height H of the heat receiving member 37, and hence the cooling structure becomes thinner. In a case where the entirety of the heat transfer member 33 is arranged within the height H of the heat receiving member 37, the cooling structure becomes further thinner.
Next, a portable computer 1 as an electronic apparatus according to a sixth embodiment of the present invention will be described below with reference to
The portable computer 1 according to this embodiment differs from the portable computer of the first embodiment in the type of the circuit board 21. The fundamental configurations of the portable computer and the cooling unit are identical with those of the first embodiment.
As shown in
The portable computer 1 and the cooling unit 26 according to each of the first to sixth embodiment have been described above. Needless to say, the present invention is not limited to these. The configurations according to the above-mentioned embodiments may be appropriately combined with each other so as to be carried out.
For example, as shown by solid lines or two-dot chain lines in
While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2007-145454 | May 2007 | JP | national |