Abstract:
An information processing unit and a method for making the same with a cooling structure for a heat generating element, for example a CPU, which can efficiently cool the CPU without losing flexibility of a board level packaging. The information processing apparatus includes a cooling unit cooling the heat generating element, an airflow supply unit supplying airflow to a part of the cooling unit, an airflow control unit controlling airflow applied to the airflow supply unit, an inlet, and an outlet. The airflow supply unit, the airflow control unit, and the part of the cooling unit are linearly arranged. The inlet is located to draw air towards the airflow control unit and the exhaust is located to exhaust air from the part of the cooling unit.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is directed to an information processing apparatus that provides a chassis with improved mechanical and thermal design efficiencies so that heat generating elements are better cooled. 
   2. Discussion of the Background 
   Because of the increased desire for CPU performance in an information processing apparatus, resulting from increased use of the Internet, more complicated processing applications, etc., the CPU is becoming more and more required to perform high load processes, for example image processing or time-varying image processing. Although CPU performance is increasing, such increased CPU performance typically also results in the CPU generating more heat. If the increased heat generated by a CPU is not efficiently dissipated the CPU performance can deteriorate. 
   As one resolution for the above problem, JP 2003-108269 discloses a main frame separated into two parts, a high temperature region and a low temperature region, by a region separation unit including a riser board and a riser bracket. In that device the internal electric devices are cooled by utilizing a CPU cooling fan, an additional fan for the high temperature regions, and by applying a power supply unit cooling fan for the low temperature region. 
   SUMMARY OF THE INVENTION 
   However, the present inventors recognized the solution in the above-noted art has drawbacks. Specifically, with such a solution the layout for implementing electric devices to a SMT (surface mount technology) substrate is restricted. In fact in such a device flexibility of a board level packaging is adversely affected. Further, in such a device it is unclear how the air dispersed by the cooling fan is ejected. 
   Accordingly, one object of the present is to provide a novel information processing unit with a novel cooling structure for a heat generating element, for example a CPU, which can efficiently cool the CPU without losing flexibility of a board level packaging. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
       FIG. 1  shows an external view of an embodiment of an information processing apparatus in accordance with the present invention; 
       FIG. 2  shows an internal view of the information processing apparatus in the embodiment of the present invention; 
       FIG. 3  shows an external view of a CPU cooling unit in the embodiment of the information processing apparatus of the present invention; 
       FIG. 4  shows an external view of a cutout part of an air duct in the embodiment of the information processing apparatus of the present invention; 
       FIG. 5  shows an external view of a CPU cooling unit holding part in the embodiment of the information processing apparatus of the present invention; and 
       FIGS. 6A and 6B  show modifications of an air duct that can be utilized in the information processing apparatus of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  shows an external view of an information processing apparatus  1  of the present invention, and  FIG. 2  shows an internal view of that information processing apparatus  1 . 
   As shown in  FIG. 1  the information processing apparatus  1  includes a cover  2  that covers the upper portion and both sides of the apparatus, which forms a part of a chassis, and a fan attachment member  3 , which houses a fan used to cool the inside of the chassis. A front cover  4  includes a first inlet member  10  and a second inlet member  8 . Both inlet members  10  and  8  include a number of intake ducts respectively. Further, each of these inlet members  10  and  8  also include at the rear surfaces filters for preventing foreign matter from entering into the information processing apparatus  1 . 
   The information processing apparatus  1  also includes a removable battery unit  5 , for example which can house a 5-inch removable battery, universal serial bus (USB) terminals  6 ,  7 , a floppy-disk drive  9 , optical disk drives  11  and  12 , for example 5-inch optical disk drives, and a power switch  13 . 
     FIG. 2  shows the information processing apparatus  1  without the upper and side cover  2  and without the front cover  4 , to thereby show the inside of the chassis. 
   As shown in  FIG. 2  the information processing apparatus  1  includes hard disk drives  15  and  16 , for example 3.5-inch hard disk drives. A mother board  17  loaded with devices such as a CPU or memory is located along the side of the chassis. A general power supply unit  23 , for example tailored to an ATX specification written by Intel is also provided. The power supply unit  23  typically includes its own fan (not shown). 
   Furthermore, the information processing apparatus  1  includes a holding member  22  to hold expansion cards inserted to extended slots of the mother board  17 . The fan housing  3  is provided to hold a fan (not shown), which for example can be model No. D08A manufactured by Nihon Densan. 
   In one operation of the device shown in  FIGS. 1 and 2 , air is drawn in from the second input member  8  and flows through a screen  14  position behind the second input member  8  into the internal space of the information processing apparatus  1 . The air is exhausted from the fan mounted in the fan attachment member  3  and the fan included in the power supply unit  23  after being warmed by the internal electric devices. With such an operation it becomes possible to exhaust heat generated from the various devices such as the floppy disk drive  9 , optical disk drives  11  and  12 , hard disk drives  15  and  16 , battery unit  5 , electronic devices loaded on the mother board  17 , and the power supply unit  23 . In addition the fan housed in the fan housing  3  and the fan included in the power supply unit  23  can exhaust part of the heat generated from a CPU on the mother board  17 . 
   One feature in the claimed invention is to provide another cooling mechanism dedicated to cooling a CPU on the mother board  17 . To realize that objective, the image processing apparatus  1  additionally includes a duct  18  as an airflow control device to control an airflow to another cooling mechanism. Air passes through the duct  18  after being drawn in through the first inlet member  10  and passing through a screen  19  directly behind the first inlet member  10 . Further, a CPU cooling fan  20  provides airflow to a CPU cooling unit. A part of the CPU cooling unit is held by the CPU cooling unit attachment device  21 . 
   The air duct  18  is a hollow duct structured from metal plates. The size of the cooling fan  20  may be, as a non-limiting example, 92 mm 2  and for example can be product No. 9A0912F02 manufactured by Sanyo Denki. CPU cooling unit attachment device  21  is located on or near the back surface of the chassis of the information processing unit  1 . An output exhaust unit  27  (shown in  FIG. 1 ) is provided to exhaust air that has passed through the duct  18  and through the CPU cooling unit attachment device  21 , and is located on the back surface of the chassis in correspondence to the position of the CPU cooling unit attachment device  21 . 
     FIG. 3  shows specifics of the CPU cooling unit, a part of which is held or supported in the CPU cooling unit attachment device  21 . The CPU cooling unit as shown in  FIG. 3  includes a fin unit  24 , i.e., a radiator unit, made from aluminum, for example made of 47 aluminum plates each with a size of 95 mm ×50 mm and each with a thickness of 0.3 mm. The fin unit  24  is cooled by the CPU cooling fan  20 . Four heat pipes  25  made from copper can contain water or another cooling liquid. The heat pipes  25  penetrate into a heat receiving unit  26  and into the fin unit  24 . The heat receiving unit  26  is positioned close against or in contact with the CPU to receive heat from the CPU. The heat received by the heat receiving unit  26  warms the cooling liquid in the heat pipes  25 , and dries off the cooling liquid inside the heat pipes  25 . The water vapor generated inside the heat pipes  25  is cooled by the fin unit  24  and then returns back to the heat receiving unit  26 . With such an operation heat picked up by the heat receiving unit  26  (from the CPU) and transferred to the heat pipes  25  is cooled in the fin unit  24 . Thereby, heat generated in the CPU can be dissipated and the CPU can be cooled. 
     FIG. 4  shows an end of the air duct  18 . The air duct  18  can include a cutout part  18 A at its bottom, and thereby mounting the air duct  18  to the information processing unit  1  can be made easier because of the location of the cutout part  18 A. In manufacturing the information processing apparatus  1 , initially the CPU cooling fan  20  and the CPU cooling unit attachment device  21  can be positioned inside the information processing apparatus  1 . Then, the bottom edge of air duct  18  which will be adjacent the first screen  19  acts as a fulcrum shaft at a predetermined position, and the opposite edge of the air duct  18  is then lowered into position next to the CPU cooling unit attachment device  21 . Thereby, the air duct  18  can be properly located without catching on the CPU cooling fan  20  or the CPU cooling unit attachment device  21 . 
     FIG. 5  shows an external view of the CPU cooling unit attachment device  21 . The heat fin unit  24  is located inside the cooling unit attachment device  21 , via the talons  21 B. The CPU cooling unit attachment device  21  can be made from an ABS resin, and is formed as a hollow element including the fin unit  24 . The CPU cooling fan  20  is attached to the CPU cooling unit attachment device  21  by attaching the CPU cooling fan  20  to the talons  21 B. The CPU cooling unit attachment device  21  also includes a receiving extension part  21 A. That extension part  21 A serves as a cover to prevent warm air, which travels over the cutout part  18 A of the air duct  18 , from traveling to other paths inside the information processing apparatus  1 , and similarly prevents air from other paths inside the information processing apparatus  1  from entering the CPU cooling unit attachment device  21 . Thereby, air passing through the air duct  18  will all pass to the CPU cooling fan  20 . 
   In view of the above-noted structure, air drawn into the first inlet member  10  passes through the screen  19  and into the air duct  18 , thereby enters the CPU cooling fan  20  and then passes through the CPU cooling unit attachment device  21 , and thereby passes through the fin unit  24  inside the CPU cooling unit attachment device  21 . The fin unit  24 , which has drawn heat from the CPU, will then be cooled by the air, and the air is then output through the output port  27 . 
   The above-noted structure includes a linear arrangement of the air duct  18 , the CPU cooling fan  20 , and the CPU cooling unit attachment device  21 . Thereby, air traveling through the air duct  18  can move smoothly without any significant air resistance barrier, which can enhance cooling of the CPU. 
   The information processing apparatus  1  can be manufactured in the following way. A chassis including at least the screen  14  and screen  19  is prepared. Basic devices are then attached to the chassis, for example the mother board  17  including the CPU, the power supply unit  23 , the power supply switch  13 , USB connectors  6  and  7 , and the fan is loaded into the fan attachment member  3 . Then, the removable battery unit  5 , the floppy-disk drive  9 , the optical disk drives  11  and  12 , and the hard disk drives  15  and  16  are loaded onto the chassis. The CPU cooling unit including the fin unit  24 , the heat pipe unit  25 , and the heat receiving unit  26 , and the CPU cooling fan  20  are then loaded into the CPU cooling unit attachment device  21 . The CPU cooling unit attachment device  21  is then attached to the chassis. Finally, the cover  2  is provided on the chassis. 
     FIG. 6  shows alternative shapes that can be utilized for the air duct  18 . 
     FIG. 6A  shows a first alternative air duct  180  that includes an enlarged inlet, but which is formed so as to be straight through in the middle.  FIG. 6B  includes an alternative air duct  181  that includes an enlarged inlet, but which is formed so as to gradually narrow. In both of these ducts the amount of input air drawn into the air ducts  180  and  181  can be increased, and thereby cooling efficiency may be able to be improved. 
   Certain overall effects realized by the image information processing apparatus  1  of the present invention are as follows. Air drawn into the second inlet member  8  can be used to mainly exhaust heat generated from the floppy disk drive  9 , optical disk drives  11  and  12 , hard disk drives  15  and  16 , the battery unit  5 , electronics loaded on the mother board  17 , and the power supply unit  23  (although that element may also include its own fan). Further, air drawn into the first inlet member  10  can be dedicated to cooling only the CPU. 
   With such a structure, electronic devices that generate less heat value can be cooled by the fan located inside the fan attachment unit  3  and the fan in the power supply unit  23 . At the same time a CPU that generates more heat can be more intensively cooled by a dedicated system. 
   In addition, as the CPU cooling unit formed of fin unit  24 , heat pipe unit  25 , and heat receiving unit  26  is constructed as a separate unit from the mother board  17 , a relatively free implementation of electronic devices loaded onto the mother board  17  can be realized in correlation with the CPU. Such a structure has fewer restrictions on a board level packaging. 
   With such a structure it is also acceptable for the fin unit  24  to be located above a level of a CPU because a liquid, for example water, is restored to the heat receiving unit  26  when a cooled liquid vapor changes to liquid and can then be transported through the inside of the heat pipes  25 . As a result the air duct  18 , the CPU cooling fan  20 , and the CPU cooling unit attachment device  21  can be located in an upper region of the information processing unit  1 . Such a layout can also make locating those elements above a level of the CPU easier, and thereby provide a more effective cooling of the CPU. The air duct  18 , the CPU cooling unit  20 , and the CPU cooling unit attachment device  21  may also, however, be located at a lower region of the information processing apparatus  1  if the CPU is located at a lower portion of the information processing apparatus  1 , although those elements are preferably still positioned above the CPU. 
   As noted above air passing through the air duct  18  is used for cooling the CPU. However, that air can be diverted for other uses for other devices that generate a relatively higher heat, for example a chip set. In that case, the heat receiving unit  26  may be formed of different portions that are located adjacent to each of the higher heat generating devices. Alternatively the heat receiving unit  26  may be set up so as to contact the CPU and such other heat generating devices as still a single unit. In fact the heat receiving unit  26  may be provided to cool only the other heat generating devices if the CPU is an element that does not generate significant heat. 
   In view of the structure noted above air is drawn in from the front surface of the image processing apparatus  1  and exhausted out its back surface. However alternative structures are available; for example air may be drawn in from a first side surface and exhausted out of another side surface of the image processing apparatus  1 . One benefit realized in the claimed invention is the linearity of the cooling unit to avoid any blockage of airflow into and ensure a smooth airflow, and such a structure could still be implemented if air is drawn in from a side surface and exhausted out of another side surface. 
   As noted above the air duct  18  may be formed of an aluminum or a metal plate. However, the air duct  18  can be formed of alternative materials, for example an ABS resin, if desired. In addition the air duct  18  can take different shapes than the shown rectangular shapes, for example can be a cylindrical shape. The air duct should preferably be able to control airflow so that it moves smoothly from input to output. 
   Also of course the size of the CPU cooling fan  20  is not limited but for example could be 92 mm 2  and could in fact take on a size that can cool the entire image processing apparatus. 
   The floppy disk drive  9 , removable battery  5 , optical disk drives  11  and  12 , and hard disk drives  15  and  16  are all optional devices and all and some of them could be removed. 
   Obviously, numerous additional modifications and variations of the present invention are possible in view of the above teachings. It is therefore to be understood that the present invention is not limited by the presently disclosed embodiments, but many modifications are readily recognizable to one of ordinary skill in the art. 
   The present application is based on and claims priority to Japanese Patent Application No. 2005-120374 filed on Apr. 18, 2005, the entire contents of which are hereby incorporated herein by reference.