Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2001-08-06
2004-05-25
Lea-Edmonds, Lisa (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S700000, C165S104330, C165S080300, C062S259200, C174S015200
Reexamination Certificate
active
06741464
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a liquid cooling system for cooling at body that is generating heat, and, in particular, to a liquid cooling system that is suitable for use in a small and/or thin electronic device.
Semiconductor devices that are used in electronic devices, such as a computer, etc., generate heat during their operation. In particular, high-integrated semiconductor devices, in recent years, have produced an increased amount of heat generation. Since the semiconductor device will be damaged if the temperature thereof exceeds a certain value, cooling is necessary to prevent damage to the semiconductor device having a large amount of heat generation during use.
For cooling the semiconductor device of an electronic apparatus, there are various known techniques, such as thermal conduction or air-cooling, or the use of a heat pipe, or liquid cooling.
Cooling by thermal conduction can be achieved by using materials having a large thermal conductivity along the heat radiation route, extending from the semiconductor device to the outside of the electronic apparatus. This method has been suitable for a so-called compact electronic apparatus, in which heat generation is relatively small, such as a notebook-type personal computer.
With cooling by the use of forced air, an air blower or fan is provided inside the electronic apparatus, thereby achieving a cooling of the semiconductor device therein by forced circulation of air thereon. This method is adopted widely for the cooling of semiconductor devices having a higher amount of heat generation, and it also has been applied to a personal computer by making the air blower small and thin in size.
Cooling with the use of a heat pipe, involves carrying heat out the outside of the electronic apparatus by means of coolant enclosed within a pipe, as described in Japanese Patent Laying-Open No. Hei 1-184699 (1989), and Japanese Patent Laying-Open No. Hei 2-244748 (1989), for example. With this method, since there is no part capable of consuming electric power therein, such as an air blower or fan, such a cooling device has good efficiency, i.e., it increases the cooling through thermal conduction. However, with this method, there is a limit to the amount of heat that can be transferred.
Cooling by means of a liquid coolant is suitable for the cooling of a semiconductor device which generates a large amount of heat, and such a cooling device is described, for example, in Japanese Patent Laying-Open No. Hei 5-1335454 (1993), Japanese Patent Laying-Open No. Hei 6-97338 (1994), Japanese Patent Laying-Open No. Hei 6-125188 (1994), and Japanese Patent Laying-Open No. Hei 10-213370 (1998). However, such a cooling system using a liquid coolant has been restricted as to its field of utilization, such as to a large-scale computer. This is because the cooling system using a liquid coolant requires a large number of parts, such as a pump, a pipe system, heat radiation fins, etc., which are used exclusively for cooling, and so the apparatus comes to be large in size. Thus, it is difficult to maintain a satisfactory reliability when using liquid for cooling compared to other methods. It is also one of the reasons why, on the commercial market, no semiconductor device requiring such a high level of cooling employs a liquid cooling system, other than in the field of large-scale computers.
A technique for adapting liquid cooling to a small-sized apparatus, including a notebook-sized personal computer, is described in Japanese Patent Laying-Open No. Hei 6-266474 (1994). In this cooling device, a header attached onto the semiconductor device and a heat radiation pipe separately located from it are connected with each other by means of a flexible tube to form a cooling system, wherein heat is transferred through the liquid coolant flowing therein, thereby cooling the semiconductor device.
However, there has been a remarkable increase in the heat generation produced from semiconductor devices which are used in electronic devices, such as a personal computer, a server computer, a work station, etc., in recent years, with the result that adoption of such conventional technique for cooling is no longer sufficient in connection with electronic apparatuses that are required to be small and thin in size, in particular, such as a notebook-type personal computer.
SUMMARY OF THE INVENTION
An object of the present invention, therefore, is to provide a liquid cooling system that is able to efficiently cool down a heat generating body in which high heat is generated, such as a semiconductor device or element of the type which is used in an electronic apparatus that is small and thin in size, and also to provide a personal computer equipped with such a cooling system.
The object, as mentioned above, according to the present invention, is accomplished by the provision of a liquid cooling system of superior efficiency, which is small and thin in size, or by a personal computer equipped with such a liquid cooling system, being peculiar to the personal computer, which is small and thin in the size thereof.
A pump is necessary for circulation of liquid in a liquid cooling system; however, with a pump of rotational type, which is typically used, it is impossible to realize, in particular, a personal computer that is ultra-small and thin, and has a low electric power consumption, as well. For this reason, it is more effective to use a pump which operates by pressurizing the liquid coolant through reciprocal movement of a member. However, even when using such a pump of the reciprocal type, it is necessary to satisfy certain conditions for the purpose of achieving a system of low electric power consumption, while enabling cooling effectively, as will be described below.
In more detail, according to the present invention, there is provided a liquid cooling system, comprising: a pulsation-type pump for supplying cooling liquid; a heat receiving jacket supplied with said cooling liquid and positioned to receive heat generated from a heat generating body; a heat radiation pipe for radiating heat which is supplied by the cooling liquid passing through said heat receiving jacket; and a passage for circulating the cooling liquid passing through said heat radiation pipe into said pump, wherein said cooling liquid circulates within a closed flow passage. In this cooling system, &Dgr;Vs is equal to or greater than &Dgr;Vp, assuming that the inner volume change when said pump emits a pulsation is represented by &Dgr;Vp, the pressure accompanying said volume change is represented by P, and the volume change due to said pressure P in the flow passage of the cooling liquid, other than in a portion of said pump, is represented by &Dgr;vs.
Further, for example, said pump emits a pulsation by the reciprocal movement of a member within the pump, and the reciprocal movement of the member in said pump is caused by bending or flexure of a diaphragm. This diaphragm itself, or a driving source of the diaphragm, is preferably formed with a piezo element, from the viewpoint achieving a of small-size, low electric power consumption and low noise, etc. With this, it is possible to maintain a substantial amount of cooling liquid in the system, even in a computer that is small and thin in size, thereby to obtain effective cooling.
Also, a rubber pipe or a resin pipe may be used as at least a portion of the connector pipe which forms the flow passage for carrying said cooling liquid therein, and the surface of said resin or rubber pipe is coated with a metal film or a resin sheet covered with a metal film, thereby suppressing diffusion of the cooling liquid through the rubber and the resin into the atmosphere and enabling conduction of heat with efficiency, as well.
The liquid cooling system defined above, preferably, further comprises an accumulator, in which the volume change of the cooling liquid therein due to said pressure P is equal to or greater than &Dgr;Vp, from a viewpoint of management of the pressure.
Further, the accumulator has a structure such that it retains
Ashiwake Noriyuki
Kitano Makoto
Kondo Yoshihiro
Minamitani Rintaro
Naganawa Takashi
Antonelli Terry Stout & Kraus LLP
Lea-Edmonds Lisa
LandOfFree
Liquid cooling system and personal computer using thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid cooling system and personal computer using thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid cooling system and personal computer using thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3187892