JP2010027649A - Circuit board and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board and electronic equipment that efficiently cool electronic components on a substrate. <P>SOLUTION: The circuit board includes the substrate 12 where outside air 30 flows over principal surfaces 12b and 12c, first electronic components 15 and 16 mounted on one principal surface of the substrate 12, a through-hole 12a formed in the substrate 12 disposed downstream from the first electronic components 15 and 16 in the flowing direction of the outside air 30, a second electronic component 14 mounted on the principal surfaces 12b and 12c of the substrate 12 and downstream from the through-hole 12a in the flowing direction of the outside air 30, and a control unit 20 capable of varying the flow rate of the outside air 30 passing through the through-hole 12a. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a circuit board and an electronic device.

  In electronic devices such as servers and personal computers, electronic components such as a memory, a chipset, and a CPU (Central Processing Unit) are mounted on a circuit board. These electronic components generate heat during operation of the electronic device, but if the heat generation is excessive, the electrical characteristics of each electronic component may fluctuate.

  For this reason, in an electronic device, outside air is forcibly taken into a housing by a fan and each electronic component is air-cooled.

  In that case, the electronic component on the leeward side with respect to the flow of the taken-in outside air is exposed to the outside air heated by the electronic component on the leeward side, so that the temperature rises and its characteristics deteriorate. Therefore, a technology has been proposed in which an air guide plate is fixed to a circuit board and the flow of the outside air is regulated so that the outside air flowing from the windward side does not hit the electronic components on the leeward side.

However, the amount of heat generated by each electronic component usually varies with time depending on the operating state of the electronic device. For example, when a large amount of data is processed in the CPU, the temperature of the CPU is higher than when the data is not. In the technique using the air guide plate as described above, even when the amount of heat generated in each electronic component fluctuates in time as described above, the air guide plate is fixed to the circuit board, so that it is assigned to each electronic component. The flow rate of the outside air is also fixed, and the outside air cannot be efficiently distributed for each electronic component according to the heat generation state of each electronic component.
Japanese Patent Laid-Open No. 7-212477 JP-A-9-274791 JP 2000-124400 A

  An object of the present invention is to efficiently cool electronic components on a circuit board and electronic equipment.

  According to one aspect of the following disclosure, a substrate through which a cooling gas passes on a main surface, a first electronic component mounted on one main surface of the substrate, and the first of the substrates. A through-hole provided at a position on the leeward side of the cooling gas with respect to the electronic component, and on the one main surface or the other main surface of the substrate, and for the cooling than the through-hole. There is provided a circuit board having a second electronic component mounted on the leeward side of the gas and an adjusting means capable of changing the flow rate of the cooling gas passing through the through hole.

  According to another aspect of the disclosure, a circuit board, a housing having the circuit board mounted therein, a cooling gas inlet and an outlet for cooling the circuit board, and the cooling A fan for introducing gas from the inflow port, and the circuit board includes a substrate through which the cooling gas passes on a main surface, and a first electronic component mounted on one main surface of the substrate A through hole provided at a position on the leeward side of the cooling gas with respect to the first electronic component, and the one main surface or the other main surface of the substrate. And an electronic device having a second electronic component mounted on the leeward side of the cooling gas with respect to the through-hole and an adjusting unit capable of changing a flow rate of the cooling gas passing through the through-hole. Is done.

  According to this circuit board and the electronic device, the flow rate of the cooling gas passing through the through hole of the board is changed by the adjusting means, so that the second electronic component on the leeward side of the through hole is used for cooling at a preferable flow rate. Cooled by gas. Further, by disposing the first electronic component on the windward side of the second electronic component, the first electronic component is prevented from being exposed to the cooling gas heated by the second electronic component. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(1) First Embodiment FIG. 1 is a perspective view of an electronic apparatus according to a first embodiment.

  The electronic device 1 is a blade server and includes a chassis 2 and a plurality of server blades 3. Each server blade 3 can be detached from the front surface 1a side of the electronic device 1 and has a plurality of inlets 3a for taking in outside air.

  FIG. 2 is a perspective view for explaining the internal structure of the electronic apparatus 1. In the figure, the server blade 3 is omitted.

  As shown, the electronic device 1 is provided with a switch blade 4, a management blade 5, a power supply unit 6, and a fan unit 7.

  Among these, the switch blade 4 has a function of consolidating LAN (Local Area Network) terminals of the server blades 3 (see FIG. 1) and connecting to external devices.

  The power supply unit 6 is used to supply power to each server blade 3, the switch blade 4, the fan unit 7, and the like.

  The fan unit 7 takes in outside air from the inlet 3a of the server blade 3 shown in FIG. 1 by the rotation of the fan 10, and air-cools each electronic component in the server blade 3.

  FIG. 3 is a cross-sectional view for explaining the flow of outside air inside the electronic apparatus 1.

  When the fan 10 rotates, outside air (cooling gas) 30 is taken into the device 1 from the inlet 3a of the server blade 3 by the suction force. The outside air 30 cools each electronic component in the server blade 3 and then exits from the outlet 3 b of the server blade 3. A back panel 3h is provided downstream of the outflow port 3b, and the outside air 30 that has passed through the opening 3e of the back panel 3h is discharged to the outside of the device by the fan unit 7. The back panel 3h is provided with a back panel side connector 3f, and the back panel 3h and the server blade 3 are mechanically connected by inserting the back panel side connector 3f into the server blade side connector 3g. .

  FIG. 4 is a partially cutaway sectional view of the server blade 3.

  As shown in the figure, the server blade 3 includes a casing 11 formed by pressing a metal plate such as iron, and a mother board (circuit board) 18 accommodated therein.

  The motherboard 18 has electronic components mounted on both sides of the double-sided wiring board 12. The double-sided wiring board 12 has a thickness of about 3 mm obtained by laminating a plurality of insulating layers and copper wirings, and includes a rectangular through hole 12a through which the outside air 30 for cooling electronic components flows. The size of the through hole 12a is not particularly limited. In the present embodiment, the short side of the through hole 12a is 10 to 50 mm, and the long side is 50 to 150 mm. The through hole 12a can be formed by mechanical processing using a drill after the double-sided wiring board 12 is completed.

  Further, a louver 21 and a stepping motor 24 are provided on the substrate 12 next to the through hole 12a as the adjusting unit 20 for adjusting the flow rate of the outside air 30 flowing through the through hole 12a. Of these, the stepping motor 24 is mechanically fixed to the substrate 12 with screws. A servo motor may be used instead of the stepping motor.

  On the other hand, the louver 21 regulates the flow of the outside air 30 passing through the through-hole 12a by a rotational movement around the rotation shaft 21a, and the rotation angle thereof can be arbitrarily set by the stepping motor 24.

  The material of the louver 21 is not particularly limited, and a louver 21 made of metal or resin can be used. Of these, the resin louver 21 is advantageous in that foreign matters such as conductive burrs are not generated, and electronic components on the substrate 12 can be prevented from being electrically short-circuited due to the conductive foreign matters. is there.

  In the present embodiment, two louvers 21 are provided in the through hole 12a, and each of them rotates synchronously at the same angle.

  Electronic components necessary for the function of the server blade 3 are mounted on the substrate 12. Such electronic components include a CPU 14, a memory module 15, and a chip set 16.

  Among these, the chip set 16 is a group of LSI elements that manage the data transfer between the CPU 14 and the memory module 15. As the memory module 15, a DIMM (Dual Inline Memory Module) in which a plurality of DRAM (Dynamic Random Access Memory) chips are mounted on one common substrate is used.

  The electronic components 14 to 16 generate different amounts of heat depending on their types, the CPU 14 generates heat to about 50 to 130 W, and the memory module 15 and the chipset 16 generate heat only to about 10 to 20 W, respectively.

  In the present embodiment, among these electronic components 14 to 16, the CPU 14 whose calorific value is higher than that of other electronic components is mounted on one main surface 12 b of the substrate 12, and the mounting position is based on the flow of the outside air 30. The leeward side of the through hole 12a.

  FIG. 5 is a partially cutaway sectional view of the server blade 3 as viewed from the other main surface 12 c of the substrate 12.

  As shown in this figure, the memory module 15 and the chip set 16 that generate less heat than the CPU 14 are mounted on the main surface 12 c on the opposite side of the CPU 14. Furthermore, the mounting position of these electronic components 15 and 16 is on the windward side of the through hole 12a with reference to the flow of the outside air 30.

  As described above, the electronic components 14 to 16 are separately mounted on both main surfaces 12 a and 12 b of the substrate 12, so that the electronic components are compared with the case where these electronic components are mounted only on one surface of the substrate 12. The space | interval of 14-16 can be taken widely.

  Therefore, the electronic components 14 to 16 can be mounted on the substrate 12 with a margin, and the memory module 15 can be mounted on the substrate 12 in a flat posture. Thereby, the thickness of the server blade 3 in the thickness direction of the substrate 12 can be reduced as compared with the case where the memory module 15 is mounted upright on the substrate 12.

  Furthermore, by setting the memory module 15 in a flat posture in this way, the flow of the outside air 30 becomes smoother than when the memory module 15 is mounted upright, and the outside air 30 is efficiently applied to the chipset 16. You can also.

  6A is a cross-sectional view taken along line AA in FIG. 4, and FIG. 6B is a cross-sectional view taken along line BB in FIG.

  As shown in FIGS. 6A and 6B, the CPU 14 and the chip set 16 are provided with heat sinks 27 and 28 made of metal such as aluminum and copper, respectively. Has been increased.

  Next, an air cooling method for the server blade 3 will be described.

  FIG. 7 is a cross-sectional view of the server blade 3 along the flow of the outside air 30.

  The outside air 30 taken in from the inflow port 3a passes over the main surfaces 12b and 12c of the substrate 12, and cools the electronic components 14 to 16.

  Here, the amount of heat generated by each of the electronic components 14 to 16 varies with time depending on the operating state of the server blade 3. For example, when the CPU 14 is processing a large amount of data, the amount of heat generated by the CPU 14 is greater than when it is not. In such a case, if the rotational speed of the fan 10 (see FIG. 3) is increased to cool the CPU 14 and the flow rate of the outside air 30 is increased, the power consumption in the fan 10 increases. Furthermore, the rotational sound of the fan 10 becomes loud and makes the user uncomfortable.

  Therefore, in the present embodiment, by opening the louver 21, a part of the outside air 30 flowing on the main surface 12 c side is taken into the main surface 12 b side from the through hole 12 a, and the flow rate of the outside air 30 that hits the CPU 14 is increased to air-cool the CPU 14. Try to increase efficiency.

  The rotation angle θ of the louver 21 measured from the main surface 12 c is controlled based on the outputs of the first temperature sensor 31 and the second temperature sensor 32 provided on the main surfaces 12 b and 12 c on the leeward side of the CPU 14. .

  The temperature sensors 31 and 32 are part of the adjusting unit 20 (see FIG. 4), and for example, a thermistor can be used.

  In this example, the temperature sensors 31 and 32 are provided on the substrate 12, but the temperature sensors 31 and 32 may be provided on the casing 11 near the outlet 3b.

Each of the temperature sensors 31 and 32 measures the temperatures T1 and T2 of the outside air 30 flowing on one main surface 12b and the other main surface 12c of the substrate 12, respectively, and the measurement results are first and second analog values. The temperature detection signals S _T1 and S _T2 are output to the management blade 5 (see FIG. 2). The management blade 5 that has received these signals S _T1 and S _T2 controls the rotation angle θ of the louver 21 as follows.

  8A and 8B are cross-sectional views for explaining a method of controlling the rotation angle θ.

  FIG. 8A shows the case where the temperature T1 of the outside air 30 flowing on one main surface 12b of the substrate 12 is equal to or lower than the temperature T2 of the outside air 30 flowing on the other main surface 12c (T1−T2 ≦ 0). FIG.

  In this case, since the temperature rise of the outside air 30 that has passed through the CPU 14 is suppressed more than the outside air 30 that has passed through the memory module 15 and the chipset 16, the CPU 14 has to be given priority to cooling the CPU 14. There is no fever. Therefore, by setting the rotation angle θ of the louver 21 to 0 ° and closing the through hole 12a with the louver 21, the outside air 30 is prevented from flowing through the through hole 12a, and independently on each side of the main surfaces 12b and 12c. The electronic components 14 to 16 are cooled by the outside air 30.

  On the other hand, FIG. 8B shows a case where the temperature T1 of the outside air 30 flowing on one main surface 12b of the substrate 12 is higher than the temperature T2 of the outside air 30 flowing on the other main surface 12c (T1-T2). > 0).

  At this time, the heat generation amount of the CPU 14 is larger than that in the case of FIG. Therefore, by setting the rotation angle θ to be larger than 0 °, a part of the outside air 30 that has passed through the memory module 15 and the chipset 16 is guided to the one main surface 12b side through the through hole 12a, and the outside air 30 that hits the CPU 14 is introduced. Increase the flow rate. Thereby, the cooling efficiency of CPU14 increases and it can cool CPU14 promptly.

  Further, by reusing the outside air 30 used for cooling the memory module 15 or the like for cooling the CPU 14 in this way, the flow rate of the outside air 30 applied to the CPU 14 can be increased without increasing the rotational speed of the fan 10. it can. As a result, it is possible to prevent an increase in power consumption and rotational noise accompanying an increase in the rotational speed of the fan 10, and energy saving and noise reduction can be achieved.

  Moreover, since the memory module 15 and the chip set 16 that generate less heat than the CPU 14 are arranged on the windward side of the CPU 14, they are not exposed to the outside air 30 heated by the CPU 14. As a result, it is possible to prevent the electrical characteristics of the memory module 15 and the chip set 16 from being deteriorated due to heating, and it is possible to maintain the reliability of these electronic components over a long period of time.

  Electronic components that generate less heat than the CPU 14 include capacitors, resistors, and the like. Even when these components are arranged on the windward side of the CPU 14, the same effects as described above can be obtained.

  Here, since the heat generation amount of the CPU 16 varies with time, it is preferable to adjust the flow rate of the outside air 30 applied to the CPU 16 over time by adjusting the rotation angle θ of the louver 21 according to the heat generation amount.

  Such adjustment of the rotation angle θ is performed in the management blade 5 as follows, for example.

  FIG. 9 is a functional block diagram of the management blade 5 according to the present embodiment.

  The management blade 5 includes an analog-digital conversion unit 35, a calculation unit 36 such as a CPU, a storage unit 37 such as a ROM (Read Only Memory), and an output unit 38.

The analog-digital conversion unit 35 converts the first and second temperature detection signals S _T1 and S _T2 of analog values output from the temperature sensors 31 and 32 into digital values.

  On the other hand, a temperature-rotation angle table 39 is stored in the storage unit 37. An example of the temperature-rotation angle table 39 will be described later.

The calculation unit 36 calculates a temperature difference T1−T2 from the digitized temperature detection signals S _T1 and S _T2 . Thereafter, the calculation unit 36 refers to the temperature-rotation angle table 39 to obtain the rotation angle θ corresponding to the temperature difference T1-T2, and outputs the rotation angle signal Sθ obtained by digitizing the rotation angle θ to the output unit 38 at the subsequent stage. Output.

Upon receiving the rotation angle signal Sθ, the output unit 38 outputs a control signal S _m necessary for the louver 21 to rotate by the angle θ to the stepping motor 24.

  FIG. 10 is a schematic diagram illustrating an example of the temperature-rotation angle table 39 stored in the storage unit 37.

In this example, when the temperature difference T1-T2 is less than the threshold temperature _Tth , the rotation angle θ is 0 °. The threshold temperature T _th is an upper limit value of an error that appears in the temperature difference T1-T2 due to a measurement error of each of the temperature sensors 31, 32, and is typically about 2 to 3 ° C. At such a temperature lower than the threshold temperature T _th , there is no confirmation that the first temperature T1 is higher than the second temperature T2, so the rotation angle θ is set to 0 ° and the motor 24 is wasted. Suppress.

On the other hand, when the temperature difference T1-T2 is equal to or higher than the threshold temperature _Tth , the rotation angle θ is increased as the temperature difference T1-T2 increases, and the flow rate of the outside air applied to the CPU 16 is increased.

  As described above, by adjusting the rotation angle θ according to the temperature difference T1-T2, the flow rate of the outside air applied to the CPU 16 can be adjusted in accordance with the heat generation amount of the CPU 16.

(2) Second Embodiment In the first embodiment described above, the rotation angles of the two louvers 21 shown in FIG. 4 are synchronized.

  On the other hand, in this embodiment, these louvers 21 configured as follows are driven independently.

  FIG. 11 is a partially cutaway sectional view of the server blade 3 according to the present embodiment. In FIG. 10, the same elements as those described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted below.

  In the present embodiment, two first temperature sensors 31 are provided on one main surface 12 b of the substrate 12 so as to correspond to each of the two CPUs 14, and the temperatures of the outside air 30 flowing over the respective CPUs 14 are determined. The temperature sensor 31 is used for independent measurement.

  The rotation angle of each louver 21 is controlled in the same manner as in the first embodiment, using the measured temperature T1 of the first temperature sensor 31 corresponding to the louver 21 and the measured temperature T2 of the second temperature sensor 32. Is done.

  Thus, by independently controlling the rotation angles of the two louvers 21, the flow rate of the outside air 30 can be changed for each CPU 14 even when the heat generation amounts of the plurality of CPUs 14 are different. The outside air 30 having a flow rate optimum for cooling each CPU 14 can be applied.

(3) Third Embodiment In the first and second embodiments, the louver 21 and the stepping motor 24 are used as the adjusting unit 20 for adjusting the flow rate of the outside air 30 flowing through the through hole 12a.

  On the other hand, in the present embodiment, the following artificial muscle is used as the adjusting unit 20.

  FIG. 12 is an enlarged cross-sectional view of the server blade 3 according to the present embodiment.

  In FIG. 12, the same elements as those described in the first and second embodiments are denoted by the same reference numerals as those of the embodiments, and the description thereof is omitted below.

  The artificial muscle 40 used as the adjusting unit 20 is a plate-like electric field-responsive polymer material having a thickness of about 500 to 2000 μm, and includes a pair of electrodes 41 provided on a part of the upper and lower surfaces. Curves according to the voltage between. The electric field responsive polymer material is not particularly limited, and a fluorine-based ferroelectric polymer material such as polyvinylidene fluoride (PVDF) or vinylidene fluoride-trifluoroethylene copolymer (P (VDF-TrFE)) is used. Can be used.

  The electrode 41 is, for example, a metal foil of gold, silver, or copper, and is fixed on the substrate 12 beside the through hole 12a by an adhesive.

  The bending angle ω of the artificial muscle 40 measured from the main surface 12c of the substrate 12 can be adjusted by the voltage between the two electrodes 41, and the bending angle ω increases as the voltage increases.

  The adjustment of the bending angle ω can be performed using a temperature-bending angle table 43 as shown in FIG. 13 instead of the temperature-rotation angle table 39 used in the first embodiment.

  In this temperature-bending angle table 43, when the temperature difference T1-T2 between the first temperature sensor 31 and the second temperature sensor 32 (see FIG. 7) is 0 ° C. or less, the bending angle ω becomes 0 °, and artificial The through hole 12a is blocked by the muscle 40.

  On the other hand, in a range larger than 0 ° C., the greater the temperature difference T 1 −T 2, the greater the bending angle ω of the artificial muscle 40 and the greater the flow rate of the outside air 30 flowing through the through hole 12 a.

  The management blade 5 obtains a bending angle ω corresponding to the temperature difference T1−T2 by referring to such a temperature-bending angle table 43, and applies a voltage necessary to obtain the bending angle ω to the electrode 41. To do.

  In the present embodiment, by using the artificial muscle 40 having no mechanical movable part in this way, the number of parts of the adjustment unit 20 can be reduced as compared with the first embodiment, and the adjustment unit 20 can be simplified. It becomes possible to plan.

(4) Fourth Embodiment In this embodiment, a shape memory alloy plate is used as the adjustment unit 20 as follows.

  FIG. 14 is an enlarged cross-sectional view of the server blade 3 according to the present embodiment.

  In FIG. 14, the same elements as those described in the first to third embodiments are denoted by the same reference numerals as those of the embodiments, and the description thereof is omitted below.

  The shape memory alloy plate 50 used as the adjusting unit 20 is mechanically fixed to the substrate 12 beside the through hole 12a by screws 51, and is bent by the heat of the CPU 14 transmitted through the substrate 12.

  When the CPU 14 does not generate heat and the temperature is room temperature (20 ° C.), the bending angle δ with respect to the main surface 12c of the substrate 12 is 0 °, and the through hole 12a is blocked by the shape memory alloy plate 50. It is.

  On the other hand, when the CPU 14 generates heat to a temperature higher than room temperature, the bending angle δ becomes larger than 0 °, and the outside air 30 flows through the through hole 12a. As a result, the CPU 14 is cooled not only by the outside air 30 that has flowed on the one main surface 12b of the substrate 12 but also by the outside air 30 that has passed through the through hole 12a, so that the temperature of the CPU 14 can be quickly lowered. it can.

  As described above, since the bending angle δ changes repeatedly according to the fluctuation of the heat generation amount of the CPU 14, it is preferable to use an alloy film having excellent bending resistance as the shape memory alloy plate 50. Examples of such an alloy include a Ni—Ti alloy, a Ni—Ti—Fe alloy, a Ni—Ti—Cu alloy, and a Fe—Mn—Si alloy. In addition, the thickness of the shape memory alloy plate 50 is not particularly limited, but in the present embodiment, it is about 500 to 2000 μm.

  By using the shape memory alloy plate 50 as described above, the bending angle δ can be adjusted without electrical control. Therefore, in this embodiment, the first temperature sensor 31 used in the first embodiment is used. The second temperature sensor 32 is not necessary, and the apparatus configuration can be simplified.

  Note that the same effect can be obtained by using a bimetal plate in which two or more metal plates having different thermal expansion coefficients are laminated instead of the shape memory alloy plate 50. Such a bimetal plate can be produced, for example, by laminating two or more iron-nickel alloy plates having different manganese contents.

  Further, since the substrate 12 is formed by laminating a plurality of copper wirings having excellent thermal conductivity, the heat of the CPU 14 is efficiently transmitted to the shape memory alloy plate 50 through the substrate 12. Therefore, the shape memory alloy plate 50 quickly responds according to the variation in the heat generation amount of the CPU 14, and the flow rate of the outside air 30 passing through the through hole 12a can be quickly adjusted.

(5) Fifth Embodiment FIG. 15 is a cross-sectional view of two adjacent server blades 3 according to this embodiment.

  In FIG. 15, the same elements as those described in the first to fourth embodiments are denoted by the same reference numerals as those of the embodiments, and the description thereof is omitted below.

  In the present embodiment, a common opening 11a is formed in adjacent casings 11, and a louver 21 is provided in the opening 11a. The louver 21 is rotated by a stepping motor as in the first embodiment. And based on the detected temperature of the 1st and 2nd temperature sensors 31 and 32 provided in each housing | casing 11, the rotation angle of the louver 21 of the opening 11a is controlled.

  The control of the rotation angle is performed by the management blade 5 as follows based on the temperature-rotation angle table 39 (see FIG. 10), as in the first embodiment.

  For example, the detected temperature of the second temperature sensor 32 provided in the upper casing 11 in the figure is T2, and the detected temperature of the first temperature sensor 31 provided in the lower casing 11 in the figure is T1. In this case, the rotation angle θ corresponding to the temperature difference T1-T2 is acquired from the temperature-rotation angle table 39.

  Then, by rotating the louver 21 of the opening 11a by the acquired rotation angle θ, a part of the outside air 30 flowing through the upper casing 11 in the figure is taken into the lower casing 11 through the opening 11a, and the casing Prioritize cooling of the CPU 14 in the body 11.

  By transferring the outside air 30 between the adjacent server blades 3 in this way, the temperature difference in the plurality of casings 11 is eliminated, and in the casing 11 that is the highest temperature when the transfer is not performed. The temperature goes down. Since the rotation speed of the fan 10 is set in accordance with the highest temperature among the plurality of casings 11, the rotation speed of the fan 10 is reduced by eliminating the temperature difference between the casings 11 in this way. Therefore, it is possible to suppress power consumption and noise caused by the fan 10.

  Although the louver 21 is used in this example, the artificial muscle described in the third embodiment may be used instead.

(6) Sixth Embodiment In the first to fifth embodiments described above, the double-sided wiring board is used as the substrate 12, but a single-sided wiring board may be used as follows.

  FIG. 16 is a cross-sectional view of the server blade 60 according to the present embodiment. In FIG. 16, the same elements as those described in the first to fifth embodiments are denoted by the same reference numerals as those of the embodiments, and the description thereof is omitted below.

  The server blade 60 includes a housing 11 and first and second single-sided wiring boards 61 and 62 housed therein. Electronic components such as the CPU 14, the memory module 15, and the chip set 16 are mounted only on one main surface 61 a and 62 a of each of the substrates 61 and 62.

  The casing 11 in the vicinity of the outlet 3b is provided with first and second temperature sensors 31, 32, and the outside air 30 passing over the main surfaces 61a, 62a of the substrates 61, 62 is provided. The temperature is measured by these sensors 31, 32.

  Further, the second single-sided wiring board 62 has a through hole 62 b through which the outside air 30 flows and the louver 21. The louver 21 is rotated by a stepping motor as in the first embodiment.

  And among each electronic component 14-16 mounted in each board | substrate 61 and 62, CPU14 is located in a leeward side rather than the through-hole 62b, and the memory module 15 and the chipset 16 are located in a leeward side rather than the through-hole 62ba. To do.

  In the present embodiment, adjustment is performed in the same manner as in the first embodiment based on the temperature T1 of the outside air 30 measured by the first temperature sensor 31 and the temperature T2 of the outside air 30 measured by the second temperature sensor 32. The rotation angle θ of the louver 21 of the unit 20 is controlled.

  As a result, when the heat generation amount of the CPU 14 mounted on the first single-sided wiring board 61 is larger than that of the CPU 14 on the second single-sided wiring board 61 and the temperature difference T1-T2 becomes larger than 0 ° C., The rotation angle θ of the louver 21 becomes larger than 0 °. As a result, a part of the outside air 30 that has passed over the second single-sided wiring board 62 is guided to the first single-sided wiring board 61 through the through hole 62b, and the CPU 14 on the board 61 is preferentially cooled. It becomes possible.

  Although the louver 21 is used in this example, the artificial muscle described in the third embodiment may be used instead.

(7) Seventh Embodiment In the first to fifth embodiments described above, the blade server is described as an example of the electronic device. However, the present invention is not limited to this, and can be applied to a personal computer as follows. .

  FIG. 17 is a perspective view of the electronic apparatus according to the present embodiment. In FIG. 17, the same elements as those described in the first to sixth embodiments are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted below.

  The electronic device 70 is a personal computer and includes a housing 71, a hard disk drive 72, and an optical disk drive 73.

  An inflow port 71 a is formed on the front surface of the housing 71, and the outside air 30 is taken into the housing 71 from the inflow port 71 a by the fan 74. The taken-in outside air 30 cools the substrate 12 in the housing 71 and then is discharged to the outside from an outflow port 71 b formed on the back surface of the housing 71.

  The substrate 12 is provided with a through hole 12a and a louver 21, and the CPU 14 mounted on one main surface 12b of the substrate 12 is cooled by the outside air 30 passing through the through hole 12a.

  Then, on the main surface of the substrate 12 opposite to the main surface 12b, the memory module 15 and the chip set 16 are mounted in a portion on the windward side of the through hole 12a.

  Furthermore, the casing 71 located on the leeward side of the substrate 12 is provided with first and second temperature sensors 31 and 32 that measure the temperature of the outside air 30 that has passed above both main surfaces of the substrate 12.

  Based on the measurement results of these temperature sensors 31, 32, the rotation angle of the louver 21 is adjusted in the same manner as in the first embodiment, and the flow rate of the outside air 30 passing through the opening 12a is adjusted.

  Thereby, when the heat generation amount of the CPU 14 is larger than the heat generation amounts of the memory module 15 and the chip set 16, the rotation angle of the louver 21 is increased and the outside air 30 passes through the opening 12a. Thereby, cooling of the CPU 14 is prioritized and the temperature can be quickly lowered.

  In this example, the louver 21 is used as the adjusting unit 20, but the artificial muscle described in the third embodiment, or the shape memory alloy plate or the bimetal plate described in the fourth embodiment may be used as the adjusting unit 20. .

  The aspects of the present invention are summarized in the following supplementary notes.

(Supplementary note 1) a substrate through which the cooling gas passes on the main surface;
A first electronic component mounted on one main surface of the substrate;
A through hole provided in a position on the leeward side of the cooling gas from the first electronic component in the substrate;
A second electronic component mounted on the one main surface or the other main surface of the substrate and mounted on the leeward side of the cooling gas from the through hole;
The circuit board comprising: an adjusting unit capable of changing a flow rate of the cooling gas passing through the through hole.

(Additional remark 2) The said adjustment means has a sensor which detects the temperature of the gas for cooling which passed the said 2nd electronic component,
The circuit board according to claim 1, wherein a flow rate of the cooling gas passing through the through hole is adjusted based on an output from the sensor.

  (Supplementary Note 3) The circuit board according to Supplementary Note 2, wherein the adjustment means includes a plate-like member that is partly fixed to the substrate, and that the other part except for the part covers the through hole. .

  (Supplementary note 4) The circuit board according to supplementary note 3, wherein the plate-like member is an artificial muscle.

(Additional remark 5) The said adjustment means has a plate-shaped member in which a part is fixed to the said board | substrate and the other part except the said part covers the said through-hole,
The circuit board according to claim 1, wherein the member is a member made of a bimetal or a shape memory alloy.

  (Additional remark 6) The said adjustment means has a louver which regulates the flow of the said cooling gas which passes the said through-hole, and a motor which rotates the said louver, The circuit board of Additional remark 2 characterized by the above-mentioned.

  (Supplementary note 7) The circuit board according to any one of supplementary notes 1 to 6, wherein a heat value of the second electronic component is larger than a heat value of the first electronic component.

(Appendix 8) Circuit board,
A housing having the circuit board mounted therein and a cooling gas inlet and outlet for cooling the circuit board;
A fan for introducing the cooling gas from the inlet,
The circuit board is
A substrate through which the cooling gas passes on a main surface;
A first electronic component mounted on one main surface of the substrate;
A through hole provided in a position on the leeward side of the cooling gas from the first electronic component in the substrate;
A second electronic component mounted on the one main surface or the other main surface of the substrate and mounted on the leeward side of the cooling gas from the through hole;
And an adjusting device capable of changing a flow rate of the cooling gas passing through the through hole.

FIG. 1 is a perspective view of the electronic apparatus according to the first embodiment. FIG. 2 is a perspective view for explaining the internal structure of the electronic apparatus according to the first embodiment. FIG. 3 is a cross-sectional view for explaining the flow of outside air inside the electronic apparatus according to the first embodiment. FIG. 4 is a partially cutaway cross-sectional view of a server blade provided in the electronic apparatus according to the first embodiment. FIG. 5 is a partially cutaway sectional view of the server blade as viewed from the other main surface of the substrate. 6A is a cross-sectional view taken along line AA in FIG. 4, and FIG. 6B is a cross-sectional view taken along line BB in FIG. FIG. 7 is a cross-sectional view of the server blade along the flow of outside air. FIGS. 8A and 8B are cross-sectional views for explaining a method of controlling the rotation angle of the louver. FIG. 9 is a functional block diagram of a management blade provided in the electronic device according to the first embodiment. FIG. 10 is a schematic diagram illustrating an example of a temperature-rotation angle table. FIG. 11 is a partially cutaway cross-sectional view of a server blade according to the second embodiment. FIG. 12 is an enlarged cross-sectional view of a server blade according to the third embodiment. FIG. 13 is a schematic diagram illustrating an example of a temperature-bending angle table. FIG. 14 is an enlarged cross-sectional view of a server blade according to the fourth embodiment. FIG. 15 is a cross-sectional view of two adjacent server blades according to the fifth embodiment. FIG. 16 is a cross-sectional view of a server blade according to the sixth embodiment. FIG. 17 is a perspective view of an electronic apparatus according to the seventh embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic device, 1a ... Front, 2 ... Chassis, 3 ... Server blade, 3a ... Inlet, 3b ... Outlet, 4 ... Switch blade, 5 ... Management blade, 6 ... Power supply unit, 7 ... Fan unit, 10 ... Fan 11, housing 12, double-sided wiring board 12 a through hole 12 b one side of double-sided wiring board 12 c other side of the double-sided wiring board 14 CPU 15 memory module 16 ... Chipset, 18 ... Motherboard, 20 ... Adjustment part, 21 ... Luba, 24 ... Stepping motor, 27, 28 ... Heat sink, 30 ... Outside air, 31 ... First temperature sensor, 32 ... Second temperature sensor, 35 ... Analog-to-digital conversion unit 36 ... calculation unit 37 ... storage unit 38 ... output unit 39 ... temperature-rotation angle table 40 ... artificial muscle 41 ... electrode 43 ... temperature-bending Degree table, 50 ... shape memory alloy plate, 51 ... screw, 60 ... server blade, 61 ... first single-sided wiring board, 62 ... second single-sided wiring board, 70 ... electronic device, 71 ... casing, 71a ... current Inlet, 71b ... outlet, 72 ... hard disk drive, 73 ... optical disk drive, 74 ... fan.

Claims (5)

A substrate through which the cooling gas passes over the main surface;
A first electronic component mounted on one main surface of the substrate;
A through hole provided in a position on the leeward side of the cooling gas from the first electronic component in the substrate;
A second electronic component mounted on the one main surface or the other main surface of the substrate and mounted on the leeward side of the cooling gas from the through hole;
The circuit board comprising: an adjusting unit capable of changing a flow rate of the cooling gas passing through the through hole. The adjusting means has a sensor for detecting the temperature of the cooling gas that has passed through the second electronic component,
The circuit board according to claim 1, wherein a flow rate of the cooling gas passing through the through hole is adjusted based on an output from the sensor.   3. The circuit board according to claim 2, wherein a part of the adjusting unit is fixed to the board, and a part other than the part includes a plate-like member that covers the through hole. The adjusting means includes a plate-like member that is partly fixed to the substrate and that other than the part covers the through hole,
The circuit board according to claim 1, wherein the member is a member made of a bimetal or a shape memory alloy. A circuit board;
A housing having the circuit board mounted therein and a cooling gas inlet and outlet for cooling the circuit board;
A fan for introducing the cooling gas from the inlet,
The circuit board is
A substrate through which the cooling gas passes on a main surface;
A first electronic component mounted on one main surface of the substrate;
A through hole provided in a position on the leeward side of the cooling gas from the first electronic component in the substrate;
A second electronic component that is mounted on the one main surface or the other main surface of the substrate on the leeward side of the cooling gas from the through hole;
And an adjusting device capable of changing a flow rate of the cooling gas passing through the through hole.

Images