Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2001-09-19
2003-01-07
Chervinsky, Boris (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S689000, C361S698000, C361S700000, C361S704000, C361S707000, C361S719000, C257S714000, C257S715000, C174S015100, C174S015200, C165S080400, C165S104330, C165S185000
Reexamination Certificate
active
06504720
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-291291, filed Sep. 25, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cooling unit used to cool a heat generating component such as a semiconductor package, a circuit module including the cooling unit, and an electronic apparatus such as a portable computer mounted with the circuit module.
2. Description of the Related Art
An electronic apparatus such as a portable computer is furnished with an MPU (Micro Processing Unit) for processing multimedia information, including text, speech, and animations. The amount of heat released from the MPU of this type tends to increase rapidly during operation as its processing speed and the number of its functions increases. In order to ensure stable operation of the MPU, therefore, the heat radiating properties of the MPU must be improved. To attain this, the MPU requires use of a radiating component such as a heat pipe for discharging its heat to the outside.
A conventional heat pipe has an outer pipe in which a liquid refrigerant is sealed. The outer pipe is formed of a hard metallic material. Thus, if the heat pipe is directly affixed to the MPU, it cannot enjoy good adhesion to the MPU, so that heat from the MPU cannot be efficiently transmitted to the heat pipe. Conventionally, therefore, a soft heat conduction sheet or thermally conductive grease is sandwiched between the MPU and the heat pipe.
The heat conduction sheet is formed of a soft rubberlike elastic body having high heat conductivity. When the MPU and the heat pipe are connected thermally to each other, the heat conduction sheet is deformed so as to compensate for lowering of the heat conductivity that is attributable to the surface roughness of the two elements or absorb a gap that hinders heat conduction. In consequence, the thermal resistance of a thermal junction between the MPU and the heat pipe is lowered, so that the heat from the MPU can be efficiently transmitted to the heat pipe.
According to the conventional arrangement, however, the heat from the MPU is transferred to the refrigerant in the outer pipe after it is transmitted from the heat conduction sheet to the outer pipe. Accordingly, the outer pipe and the heat conduction sheet are inevitably interposed between the MPU as a heat source and the refrigerant that receives the heat, and cause a heat transfer loss. In consequence, the quantity of heat that can be transmitted from the MPU to the refrigerant is limited.
Higher-speed multifunctional versions of MPUs for portable computers are expected to be developed in the near future, and the amount of heat released from the MPUs is supposed to increase considerably. According to the conventional structure for thermal connection that uses the heat conduction sheet, therefore, there is a possibility that the cooling performance of the MPUs satisfactory or is limited. Thus, in consideration of the increase in the heat release value of modern MPUs, the rate of conduction of heat from the MPU is not to the refrigerant must be improved.
BRIEF SUMMARY OF THE INVENTION
The present invention has been contrived in consideration of these circumstances, and its object is to provide a cooling unit, circuit module, and electronic apparatus, designed so that heat from a heat generating component can be efficiently transmitted to a refrigerant and the cooling performance of the heat generating component can be improved.
In order to achieve the above object, a cooling unit according to a first aspect of the present invention comprises a vessel filled with a refrigerant. The vessel includes a heat receiving portion for receiving heat from a heat generating component, a heat dissipating portion for dissipating the heat from the heat generating component, and a heat transfer portion for transferring the heat from the heat generating component, transmitted to the heat receiving portion, to the heat dissipating portion via the refrigerant. That part of at least the heat receiving portion of the vessel which receives the heat from the heat generating component is formed of a soft heat conduction sheet capable of elastic deformation, the heat conduction sheet being directly in contact with the heat generating component.
In order to achieve the above object, a cooling unit according to a second aspect of the invention comprises a heat receiving portion for receiving heat from a heat generating component, a heat dissipating portion for dissipating the heat from the heat generating component, and a heat transfer portion for circulating a refrigerant between the heat receiving portion and the heat dissipating portion and transferring the heat from the heat generating component, transmitted to the heat receiving portion, to the heat dissipating portion via the refrigerant. That part of at least the heat receiving portion which receives the heat from the heat generating component is formed of a soft heat conduction member capable of elastic deformation, the heat conduction member being directly in contact with the heat generating component.
In order to achieve the above object, an electronic apparatus according to a third aspect of the invention comprises a housing having a heat generating component therein and a cooling unit held in the housing. The cooling unit includes a heat receiving portion for receiving heat from the heat generating component, a heat dissipating portion for dissipating the heat from the heat generating component, and a heat transfer portion for transferring the heat from the heat generating component, transmitted to the heat receiving portion, to the heat dissipating portion via a refrigerant. That part of at least the heat receiving portion of the cooling unit which receives the heat from the heat generating component is formed of a soft heat conduction sheet capable of elastic deformation, the heat conduction sheet being directly in contact with the heat generating component.
According to this arrangement, the soft heat conduction sheet can be deformed into any desired shape. Therefore, it can adhere to the heat generating component so as to compensate for lowering of the heat conductivity that is attributable to the surface roughness of the heat generating component or absorb a gap that hinders heat conduction. Accordingly, only the heat conduction sheet is interposed between the heat generating component and the refrigerant, so that the thermal resistance of a heat conduction path that extends from the heat generating component to the refrigerant can be lowered. Thus, the heat transmitted from the heat generating component to the heat conduction sheet can be efficiently transferred to the refrigerant.
In order to achieve the above object, a cooling unit according to a fourth aspect of the invention comprises a thermally conductive main body including a heat receiving portion for receiving heat from a heat generating component and a heat dissipating portion connected thermally to the heat receiving portion, a fan for supplying cooling air to the heat dissipating portion, and a refrigerant passage in the main body for moving a liquid refrigerant between the heat receiving portion and the heat dissipating portion. The refrigerant passage transfers the heat from the heat generating component, transmitted to the heat receiving portion, to the heat dissipating portion via the refrigerant. That part of the refrigerant passage which corresponds to the heat receiving portion is formed of a soft heat conduction sheet capable of elastic deformation. The heat conduction sheet is directly in contact with the heat generating component.
In the arrangement described above, the heat transmitted from the heat generating component to the heat receiving portion is diffused by heat conduction to the heat dissipating portion and transferred from the heat receiving portion to the refrigerant in the refrigerant passage. Si
Chervinsky Boris
Kabushiki Kaisha Toshiba
LandOfFree
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