Heat exchange – With retainer for removable article – Electrical component
Reexamination Certificate
2000-04-18
2001-03-06
Leo, Leonard (Department: 3743)
Heat exchange
With retainer for removable article
Electrical component
C165S121000, C174S016300, C361S697000, C415S178000
Reexamination Certificate
active
06196300
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a heat sink, and in particular to a heat sink which may be used for cooling integrated circuits, laser devices, electric or other electronic devices.
Heat sinks are known to comprise a plate, generally made of aluminum and provided on the top with cooling fins or pins, which directly contacts the housing containing the integrated circuits, in order to increase the heat exchange between the housing and the outside environment, and thus reducing the temperature of the circuit junctions. Since in the last years the size and the power of the integrated circuits are increased in geometric progression, these known heat sinks are no longer capable of dissipating the heat generated by the new circuits. Therefore, new heat sinks have been designed comprising an axial cooling fan arranged above the fins in order to increase the heat exchange between the heat sink and the surrounding air.
In order to reduce the size of the heat sink and optimize its thermal efficiency, such a cooling fan is arranged straight above the cooling fins, wherefore the air flow generated by the fan perpendicularly hits the conductive plate, resulting in turbulence and pressure drops which greatly reduce the heat exchange and thus the heat sink efficiency. Furthermore, the central portion of these known heat sinks is more heated, but the air flow coming from the fan is here reduced. In fact, for space requirements, the fan motor is inserted into the hub of the bladed rotor generating the air flow, so that it tends to outwardly flow without affecting the column of air between the rotor hub and the plate.
In order to overcome such drawbacks, a fan could be used with a larger rotor and a more powerful motor, but this solution would result in a more bulky and noisy heat sink, with evident problems when used inside an electronic device.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is thus to provide a heat sink free from such drawbacks, i.e. a heat sink which is silent, small-sized and having a high heat exchange between the conductive plate and the surrounding air. Such an object is achieved by a heat sink having the main features specified in claim
1
.
Thanks to the special upper profile of the conductive plate of the heat sink according to the present invention, the air flow hitting it in a substantially perpendicular direction is deflected towards its edges with a substantially horizontal outlet direction, resulting in an improvement of the heat sink aerodynamics. Moreover, the greater thickness at the centre of the conductive plate increases its thermal capacity and conductivity, so that the greater heat amount at the centre of the integrated circuit is homogeneously conveyed and spread throughout the upper surface of the heat sink. The increased thermal capacity of the conductive plate is also advantageous for allowing the absorption of possible sudden changes of heat, due to a sudden intensive use of the integrated circuit. Finally, since the central portion of the conductive plate is relatively thick, it is possible to provide a cavity wherein a safety thermal sensor may be conveniently housed.
Another advantage of the heat sink according to the present invention is the fact that the shape and the arrangement of the cooling fins help to improve the aerodynamics and accordingly the heat exchange of the heat sink. In fact, the conductive plate and the cooling fins form together a member which, by virtue of its structure, similar to a rotor for centrifiugal pumps, exploits at the best the air flow in order to obtain the cooling of the heat sink.
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Leo Leonard
Seidel Gonda Lavorgna & Monaco, PC
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