Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2002-03-29
2003-11-25
Thompson, Gregory (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C165S080300, C165S104330, C165S121000, C165S126000
Reexamination Certificate
active
06654245
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cooler for an electronic unit that is used for cooling a central processing unit (CPU) in a notebook-sized personal computer, and an electronic unit with the cooler, and more particularly to an electronic-unit cooler and an electronic with the cooler in which the cooling performance has been enhanced.
2. Related Art
In notebook-sized personal computers, the amount of heat generated in a CPU increases, as the CPU is operated at a higher speed. For this reason, there has been a demand for cooling of the CPU, and a wide variety of coolers for an electronic unit have been proposed.
The CPU cooler disclosed in Published Unexamined Patent Application No. 2000-323880 utilizes a heat pipe. The heat pipe transfers the heat of a CPU to the entire keyboard and discharges the heat to the outside through the entire keyboard. The heat pipe also transfers the heat to a cooling fan and discharges the heat by forced cooling.
In the CPU cooler disclosed in Published Unexamined Patent Application No. 2000-13065, a CPU and a fan are horizontally disposed adjacent to each other. A heat sink covers the top surfaces of the CPU and the fan, and a heat pipe extends along the side portion of the heat sink. The heat of the CPU is transferred toward the fan through the heat sink and the heat pipe. In this manner, the heat is discharged by forced cooling.
In the CPU cooler disclosed in Published Unexamined Patent Application No. 2000-277964, one portion of a heat sink covers a CPU, and a fan disposing space is provided inside another portion of the heat sink. A heat pipe is attached to the heat sink and extends from the CPU to the air exhaust portion of the fan disposing space and is cooled by a cooling wind within the air exhaust port
In the aforementioned CPU of Published Unexamined Patent Application No. 2000-323880, the cooling performance is insufficient, because only the heat pipe transfers the heat of the CPU toward the fan.
In the aforementioned CPU of Published Unexamined Patent Application No. 2000-13065, the heat pipe is curved and extended at right angles along the side portion of the heat sink and transfers heat from the central portion of the heat sink to the radially outer portion through the heat sink. Because of this, the cooling performances of the heat pipe and the heat sink are not high as a whole.
In the aforementioned CPU of Published Unexamined Patent Application No. 2000-277964, cooling of the heat pipe is performed at the outlet port. Because of this, the heat pipe is long in length and the refraction becomes greater. As a result, the heat transfer performance is reduced. In addition, the heat pipe is of a round pipe type and therefore requires a large cooling plate to assure a radiation surface.
It is an object of the present invention to enhance the performances of the heat sink and the heat pipe, in an electronic-unit cooler for discharging the heat of a heat generating body by forced air cooling.
Another object of the invention is to provide an electronic unit equipped with a heat sink and a heat pipe having enhanced performance.
SUMMARY OF THE INVENTION
In accordance with a first embodiment of the present invention, there is provided a cooler for an electronic unit, including:
a heat sink having (a) a first portion which contacts with a heat generating body directly or through material which efficiently conducts heat, and (b) a second portion defining at least a portion of a fan disposing face;
a fan disposed in the fan disposing space; and
a heat pipe mounted on the heat sink (a) in contact with the heat generating body directly or through the material at the first portion and (b) exposed to the fan disposing space at the second portion.
The aforementioned material includes, for example, grease and/or a high heat-conductive metal member described later. The heat generating body is, for example, a semiconductor device. The semiconductor device includes a semiconductor chip (e.g., a CPU chip) and a semiconductor package that houses the semiconductor chip at least partially in the interior thereof. The electronic unit is, for example, a notebook-sized personal computer, a portable electronic unit, etc. The heat sink is constructed, for example, of an aluminum die casting or a copper die casting. The aluminum die casting is inferior in heat conductivity to the copper die casting, but superior in weight reduction to the copper die casting.
Within the heat pipe, the interior liquid is evaporated by the heat of the heat generating body and cools the heat generating body. The vapor is cooled at the portion, on the side of the heat sink, of the heat pipe by the fan cooling air introduced to the interior surface of the heat sink. The vapor is liquefied and returned toward the heat generating body. The heat sink transfers the heat from the heat generating body, toward the fan disposing space and is cooled in the fan disposing space by the cooling wind caused by the fan.
In a conventional electronic-unit cooler, the heat pipe is mounted on the top surface, that is, the surface opposite to the heat generating body and the fan. However, in the present invention, the heat pipe is exposed to the heat generating body side and the fan disposing space side. Therefore, the absorption of heat from the heat generating body by the heat pipe, and radiation in the fan disposing space, are efficiently performed. This enhances the performance of the electronic-unit cooler significantly.
Further according to the present invention, the fan has a plurality of blades which rotate with a vertical direction of the heat sink as its axis of rotation so that air introduced in the vertical direction is discharged in a radial direction as a horizontal direction. The fan and the heat generating body are disposed side by side in a horizontal direction of the heat sink. Also, the first and second portions are continuous to each other and spread substantially horizontally above the heat generating body and the fan. Furthermore, the heat pipe extends substantially horizontally along the bottom surface of the first and second portions.
In the notebook-sized personal computer, for example, there is a demand for weight reduction and thinning of the main body. In the fan, because of the rotating blades, the dimension in the rotation direction dimension is much smaller than the radial dimension. Therefore, the rotation axis of the rotating blades is reduced in the up-and-down direction. As a result, the thickness of an electronic unit that is mounted in the electronic-unit cooler can be suppressed. The first and second portions of the heat sink spread horizontally, and transfer the heat of the heat generating body to the fan disposing space, while suppressing the height of the electronic-unit cooler. The heat pipe also extends horizontally. The horizontal structure of the heat pipe with no step portion smoothens both the movement of the vapor within the heat pipe from the heat generating body toward the fan disposing space, and the return of liquid from the fan disposing space toward the heat generating body. Thus, the heat pipe is capable of greatly enhancing its performance by extending horizontally along the first and second bottom surfaces
According to an electronic-unit cooler of a third aspect of the present invention, the second portion has a top surface lower than the top surface of the first portion. Also, the lower top surface has an inlet port communicating with the fan disposing space and also reaches at least one side surface of the heat sink.
In the notebook-sized personal computer, for instance, the thickness of the main body in which an electronic-unit cooler is mounted is small, and the gap between the top wall of the housing of the main body and the top surface of the heat sink is small. If a lower top surface area opening to at least one side surface of the heat sink is formed on the top surface side of the heat sink, and an upper inlet port is formed in the lower top surface area, an air flow passage with a predet
Horiuchi Mitsuo
Kawashima Nobuyuki
Matsui Yohichi
Grosser George E.
International Business Machines - Corporation
Reid Scott W.
Thompson Gregory
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