Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-08-20
2001-01-30
Picard, Leo P. (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S694000, C361S695000, C361S697000, C361S704000, C361S719000, C361S720000, C174S016300, C174S016100, C165S080300, C165S185000, C257S718000, C257S727000, C257S719000
Reexamination Certificate
active
06181556
ABSTRACT:
TECHNICAL FIELD
This invention relates to heat dissipators for electronic devices. More particularly, it relates to a thermally-coupled heat dissipation apparatus for use with high-heat generating solid state electronic components and devices.
BACKGROUND ART
Heat can have detrimental effects on any solid state electronic device if not properly monitored and controlled. Unfortunately, heat is a natural occurring by-product of any working solid state electronic device. This is due to the intimate relationship between heat and power. As a solid state device draws power and completes its task to which it is designed to accomplish, heat is generated. In some devices, the heat generated, and therefore subjected upon the device, is low in comparison to the total “heat stress” that the device can stand. In other devices however, heat is the enemy.
Nowhere is heat more detrimental in a solid state electronic device than in semiconductors. In particular, the heat generated by a central processing unit (CPU) of a computer, if not properly dissipated, is certain to destroy the CPU. As technical advancements increase the speed of computer CPUs, so causes the need for more power to run the faster CPUs, and hence more heat is generated. Improvements upon heat dissipators for computer CPUs have been developed. But as will be shown, these improvements are falling well short of the need for a superior heat dissipator for fast-speed, high-heat generating computer CPUs.
The heat generated by an older style CPU, such as a 286 or 386 based processor, did not require the use of a heat dissipator. The heat generated by these processors was merely allowed to dissipate through convection cooling—heat transfer by the natural upwardly flow of hot air from the processor. But as CPUs advanced, such as the 486, Pentium and other faster processors, a need for additional cooling was required. Typically, these faster CPUs were equipped with a heat sink mounted on top of the CPU and a fan mounted on top of the heat sink for blowing air through the heat sink fins towards the top of the CPU. Such a cooling device can be seen in U.S. Pat. No. 5,603,374 to We. Unfortunately, this device has many deficiencies. In particular, the device relies on a single heat sink and fan assembly. This type of configuration may be adequate for an older style processor, such as a 486-based processor, but is surely not adequate for dissipating the heat generated by Pentium-based and other faster style processors. Further, the single fan assembly does not provide any redundancy to the heat dissipation system. If the single fan fails, the cooling system will not provide the necessary cooling ability required. The result is thermal run-away of the CPU and its subsequent failure in operation. Still further, the “stacking” of a heat sink and fan on top of a processor tends to cause spacing problems when used with today's processors. This can be attributed to the large heat sinks required for today's processors. The size of the heat sink tends to be proportional to the amount of heat generated by a fast-speed processor. In other words, very fast processors require very large heat sinks. Further, many of today's processors are mounted on a daughter board which in turn plugs into the motherboard at a ninety degree angle (i.e., Slot 1 or Slot A configuration), distinguishing those mounted directly to the motherboard in a parallel relationship (i.e., Socket 7 configuration)—also known as a “socketed” processor. The daughter board mounts (Slot 1 or Slot A) require the conservative use of space, especially when a pair of mounts or slots are provided for dual processing capabilities.
In an effort to limit the size of the heat sink, various improvements were made in order to provide a superior heat sink having a low profile. Such can be seen in U.S. Pat. No. 5,794,685 to Dean. The device shown therein employs a heat sink for mounting directly to the CPU having a generally circular shape. A single fan mounts to the top of the heat sink. This low profile device attempts to provide greater heat dissipation through matching the form of the heat sink to the blade configuration of the fan. Although this cooling system may provide greater cooling effects than that seen in the We device, it still falls short of providing adequate cooling for the faster processors used in today's computers. Further, this system would not work well with a CPU mounted on a daughter board, due to the fact that the circular-shaped heat sink does not provide an adequate means for attaching the heat sink and fan to the CPU. All daughter board mounted cooling assemblies require some form of mounting means which will retain the cooling system to the CPU when the daughter board is plugged into the motherboard at the ninety degree angle. Still further, this system does not provide adequate redundancy, in that only one fan is employed.
Attempts to limit the profile of the cooling system to provide adequate cooling to today's faster CPUs can be seen in U.S. Pat. No. 5,309,983 to Bailey, U.S. Pat. No. 5,615,084 to Anderson et al. and U.S. Pat. No. 5,873,406 to Hong. Each of these cooling systems employs some type of single heat sink and single fan assembly, wherein the fan rests in an alcove formed in the heat sink. Each system addresses the problem of limited spacing inside of a computer, but does not adequately address other problems inherent in the prior art. For instance, none of these devices contemplate the use of more than one fan. Accordingly, redundancy is not provided and the failing of the fan results in inadequate cooling capabilities (thermal run-away of the processor). Further, although spacing is addressed in these devices, the need for additional cooling elements for faster-speed CPUs is not contemplated. Accordingly, these devices may not adequately cool current and future processors.
To address the high heat problem of the faster speed processors, such as Pentium-based processors, certain improvements have been made for attempting to adequately cool these devices. U.S. Pat. No. 5,353,863 to You teaches a Pentium CPU cooling system including a heat sink mounted on top of the CPU and a fan mounted to the side of the heat sink. The invention herein attempts to utilize the fan to blow the heat generated by the CPU, and conducted through the heat sink, out of the computer case. Unfortunately, this device is very “product specific.” Nowhere is it taught that the invention can be employed on a daughter board mounted CPU. In fact, this invention requires that the CPU be mounted on the motherboard in a location proximal to the computer housing vents, so that the hot air can be expelled out of the case through the vents. Further, no redundancy is suggested. Accordingly, upon failure of the single fan, the entire cooling system fails.
Other attempts to cool the faster processors can be seen in U.S. Pat. No. 5,771,153 to Sheng and U.S. Pat. No. 5,835,347 to CCU. Each of these inventions teach a system for cooling fast speed processors which are provided to consumers in plastic cases (i.e., Pentium-II or Pentium-III based processors). Unfortunately, these devices are very product specific. Each teach a cooling system which can be attached to the plastic case of the processor. Both require special clip mechanisms for attaching to the plastic case. Neither prior art reference suggest any form of redundancy and both rely on the single fan, single heat sink assembly.
Other various attempts at improved cooling systems have been attempted. U.S. Pat. No. 5,457,342 to Herbst II teaches a traditional prior art “stacked” cooling system with an additional cooling element—namely, a Peltier Effect cooling module. Peltier Effect cooling modules are electrical “heat pumps” which conduct heat from one side of the module to another through a conductor layer. Accordingly, when working properly, there is one hot and one cold side on any Peltier Effect module. In the prior art, Peltier Effect modules are inserted between the CPU and the heat sink. When working properly, the
Chervinsky Boris L.
Larson James E.
Larson & Larson P.A.
Picard Leo P.
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