KR100483079B1 - Active Micro Cooler - Google Patents

Abstract

The present invention provides an evaporator attached directly to a heat source to vaporize the refrigerant, a compressor to suck and compress the vaporized refrigerant gas, a condenser to release heat from the refrigerant while condensing the compressed refrigerant gas, and a conduit to allow the condensed refrigerant to enter the evaporator. And an expansion valve provided on the conduit to expand the condensed refrigerant. The evaporator and the condenser are provided with heat transfer enhancing means on a plate-like member having a circumference, and a predetermined number of channel connections for moving the refrigerant are formed. According to the active microcooler according to the present invention, the structure is relatively simple, the cooling capacity is larger than that of the passive cooler, and the piezo actuator is used as a driving means, so that even if it is made small so as to be the size of a semiconductor chip such as an MPU of a computer, a sophisticated operation is achieved. Achievable micro coolers can be implemented.

Description

Active Micro Cooler

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro cooler. More particularly, the present invention relates to a temperature of a semiconductor chip which generates a large amount of heat even though it is small, such as a microprocessor unit (MPU) of a computer or an integrated circuit of a mobile communication device. A micro cooler for maintaining a temperature that may not affect the performance of a semiconductor chip.

Numerous transistors are integrated in the main chip of the computer's central processing unit. This density is expected to increase further, according to Moore's Law, which states that the price of a chip is halved and performance doubles every 18 months. For example, Intel's popular Pentium 4 chip contains about 42 million transistors. According to Moore's law, a CPU chip with about 250 million transistors is expected in 2010. As expected by Moore's law, the higher the degree of integration, the more energy is consumed to perform calculations using transistors integrated on small chips, resulting in a large amount of heat generated on the chip surface. In the case of a semiconductor chip, its performance changes sensitively with temperature. Accordingly, how to deal with a large amount of heat generated on the chip surface, which greatly affects the performance of the semiconductor chip, has been a great issue.

Conventionally, personal computers have been cooled by attaching a fan on the CPU. In addition, by adding a fin (fin) structure to improve the cooling performance. However, a lot of noise is generated when the fan rotates, and it has been unsuitable for application to chips used in notebook computers or mobile communication devices which are miniaturized.

In order to solve this problem, researches are being actively conducted on micro coolers having a size of a semiconductor chip and directly connected to a heat generating chip to maintain a constant temperature of the chip. The mainstream of this research is the passive micro cooler that does not require extra power. Some passive coolers use high thermal conductivity materials to connect chips (hot parts) that generate a lot of heat with the low temperature parts so that heat is naturally conducted to the low temperature parts and is released.The heat generated from the high temperature parts causes the refrigerant to vaporize and convection. Is a passive cooler that circulates refrigerant evaporated by heat to a low temperature part, such as a micro capillary pumped loop (CPL), a micro heat pipe, or a combination of a micro heat pipe and a heat spreader. have. These passive micro coolers have had the disadvantage that the amount of heat released per hour is too small to be used in current semiconductor chips.

On the other hand, in order to manufacture a micro cooler with a larger heat release rate per hour, it is composed of a compressor, an evaporator, an expander and a condenser as in the configuration of a conventional cooler, and manufactured by a separate power to produce a micro cooler that can maximize the cooling capacity. Attempts are being made. However, most of the micro coolers being developed are not easy to manufacture as small as the size that can be directly applied to the semiconductor chip, or the temperature of the semiconductor chip, which is more integrated due to insufficient cooling capacity, does not affect the performance. There has been a problem with difficulty maintaining the level.

The present invention is to solve the above-mentioned conventional problems, the object of the present invention should be easy to manufacture to the size that can be applied to the semiconductor chip, the cooling capacity is large enough to increase the degree of integration and the amount of heat generated It is to provide an active micro cooler that can maintain the temperature of the semiconductor chip at a level that does not affect the performance of the semiconductor chip.

An object of the present invention as described above, an evaporator attached directly to the heat source to vaporize the refrigerant, a compressor for sucking and compressing the vaporized refrigerant gas, a condenser for releasing heat from the refrigerant while condensing the compressed refrigerant gas, the condensed refrigerant is It is achieved by providing an active micro cooler consisting of a conduit to be introduced into the evaporator, and an expansion valve provided on the conduit to expand the condensed refrigerant.

Here, the evaporator is preferably provided with a heat transfer enhancing means on the plate-shaped member with a wall around the periphery, and a predetermined number of channel connecting portions for allowing the evaporated refrigerant to move to the compressor.

Here, in the compressor, a predetermined number of compression means are symmetrically disposed on the plate member to compress the refrigerant below the plate member and to discharge the refrigerant above the plate member, and the refrigerant condensed in the condenser may move toward the evaporator. It is preferable that a through hole is formed.

In addition, the compression means, the pressure chamber provided therein, a diaphragm which constitutes the outer wall of the pressure chamber and can change the volume of the pressure chamber by deformation, suction that can be opened and closed to suck the refrigerant into the pressure chamber Preferably, the valve comprises a valve, a discharge valve which can be opened and closed to discharge the refrigerant from the pressure chamber, and a channel through which the compressed refrigerant can move in the condenser direction.

On the other hand, wherein the diaphragm is driven by a predetermined number of piezo actuators symmetrically arranged on the diaphragm, and the intake valve and the discharge valve are driven by piezo actuators respectively disposed on the intake valve and the discharge valve. desirable.

Here, the condenser is provided with a predetermined number of channel connecting portions for allowing the evaporated refrigerant to flow into the condenser, and is composed of a plate-like member having a wall around it, and is provided with heat transfer enhancing means on the plate-like member. It is preferable that a through hole is formed in which the used refrigerant can move toward the evaporator.

Here, the conduit is preferably connected to the through hole formed in the compressor or the condenser.

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

1a to 1c show an active micro cooler according to the invention.

As shown in FIG. 1A, an active micro cooler 10 according to the present invention can be used directly attached to the MPU 30 of a computer. FIG. 1B shows an enlarged view of the portion A shown in dashed lines in FIG. 1A. As shown in FIGS. 1A and 1B, the active micro cooler 10 is directly attached on the MPU 30 to extract heat generated from the MPU 30 and heat through the heat pipe 20. Discharge to the diffuser 40. Independently of using the heat spreader 40, a method of discharging heat of a high temperature portion of the micro cooler may be used by attaching a fan to the top of the active micro cooler 10.

1C shows an exploded perspective view of the active micro cooler 10.

As shown in FIG. 1C, the active micro cooler 10 according to the present invention includes an evaporator 100 attached directly to a heat source to vaporize a refrigerant, a compressor 300 to suck and compress the vaporized refrigerant gas, and a compressed Condenser 400 for releasing heat from the refrigerant while condensing the refrigerant gas, a conduit for introducing the condensed refrigerant into the evaporator, and an expansion valve provided on the conduit to expand the condensed refrigerant.

As shown in Figures 1a to 1c, the active micro cooler 10 according to the present invention is installed directly above the place where the evaporator 100 is to be cooled (in this embodiment, the MPU 30), The compressor 300 and the condenser 400 may be sequentially stacked on the evaporator 100 to have a structure that may be compactly assembled in a multilayer manner.

However, the content of the present invention is not limited to the cooler installed in a multi-layered manner. Although not shown in the drawings, when the installation space is constrained, the evaporator 100, the compressor 300, and the condenser 400 may be installed on the same plane, but not all components. Alternatively, the evaporator 100, the compressor 300, and the condenser 400 may be arranged to be spaced apart from each other in order to avoid backflow of heat between each other.

2A-2F an embodiment of the evaporator 100 is shown.

As shown in Figures 2a to 2f, the evaporator 100 is composed of a plate-like member having a wall around it and a predetermined number of channel connections 102 to allow the evaporated refrigerant to move to the compressor 300. . Preferably, the plate member of the evaporator 100 may be made of a disc shape. The interior of the evaporator 100 may be made of only an empty space (FIG. 2a), or may be provided with heat transfer promoting means to increase the evaporator capacity of the evaporator. The heat transfer promoting means is preferably a centrifugal channel (101) is formed to promote the refrigerant flowing from the upper portion from the central portion of the evaporator. The centrifugal channel 101 may have a cross section of a quadrangular shape (FIG. 2B), a triangle (FIG. 2C), a convex shape (FIG. 2D) or a concave shape (FIG. 2E). In addition, a plurality of fins 105 may be used as the heat transfer promoting means. The plurality of pins 105 may have a cylindrical shape or a square pillar shape. The evaporator 100 is attached directly on the MPU chip 30 serving as a heat source to evaporate the refrigerant with the heat generated by the MPU chip 30.

The evaporator 100 may be manufactured in large quantities by micro molding using a mold manufactured by a semiconductor process, a LIGA process, or a micro discharge process.

3 is a perspective view of a heat insulating plate 200 located between the evaporator 100 and the compressor 300 or between the compressor 300 and the condenser 400 of the active micro cooler according to the present invention. The insulation plate 200 is installed between the evaporator 100 and the compressor 300 or between the compressor 300 and the condenser 400 to prevent heat from flowing back from the high temperature portion of the active micro cooler 10 to the low temperature portion. It is desirable to be.

The insulation plate 200 may be manufactured in large quantities by micro molding using a mold manufactured by a semiconductor process, a LIGA process, or a micro discharge process.

4 shows a perspective view of a compressor 300 according to the invention.

As shown in FIG. 4, the compressor 300 has a predetermined number of receiving grooves 304 formed on the plate member, and compression means 310 is disposed in the receiving groove 304. The receiving groove 304 is disposed symmetrically on the plate-like member to compress the refrigerant under the plate-like member and send it out above the plate-like member. A through hole 302 is formed in the center of the compressor, and the through hole 302 is used as a conduit through which the refrigerant condensed in the condenser 400 moves toward the evaporator 100. The through hole 302 provided in the center of the circular plate is preferably made of about several tens of ㎛.

In this embodiment, as shown in Figure 4, the plate-like member is made of a circular plate, each of the six compression means 310 is formed in the receiving groove 304 formed at 60 ° along the circumferential direction of the circular plate It is arranged. The circular plate may be made about 10 mm in diameter, and the diameter of the compression means may be made about 2 mm.

5a to 5c show a first embodiment of the compression means 310 constituting the compressor 300 of the active micro cooler according to the invention.

As shown in Figures 5a to 5c, the first embodiment of the compression means 310 used in the compressor of the active micro cooler according to the present invention is a diaphragm (313, 314) on the upper and lower portions of the circular plate 315 It is attached to each, the upper diaphragm 313 is formed with a discharge port 316, the lower diaphragm 314 is formed with a suction port 328. The diaphragms 313 and 314 are driven by piezo actuators 317 to 320 or 322 to 325 provided symmetrically on the diaphragm, and the outlet 316 and the suction port 328 are attached to the flip and the flip, respectively. It is opened and closed by the discharge valve 311 and the suction valve 312 composed of the piezo actuator (321, 326). The large arrow shown in FIG. 5C indicates the direction in which the refrigerant flows, and the small arrow indicates the direction in which the discharge valve 311 and the suction valve 312 open and close.

The compression means 310 may be manufactured by a semiconductor process. That is, by appropriately dividing the layers, processes such as wet etching, deep reactive ion etching (DRIE), chemical vapor deposition (CVD), etc. are prepared in parallel with the photolithography process, and the respective layers are combined by a wafer bonding process. Try to achieve a symmetrical structure. The discharge valve 311 and the suction valve 312 may be manufactured by using a sacrificial layer. On the other hand, the manufacturing method of the compression means may be manufactured not only by the semiconductor process but also by micro molding or LIGA (LIthographie, Galvanoformung, Abformung) process.

6a and 6c show side views of piezo actuators 317 to 326 for driving compression means 310 according to the invention.

As shown in FIG. 6A, the piezo actuators 317 to 326 driving the compression means 310 of the present invention insert an elastic body 333 between two thin plate-like piezoelectric elements 331 and 332. It is made by combining with each other. The piezoelectric elements 331 and 332 have a characteristic of being stretched or compressed according to a direction in which a voltage is applied. When the voltage is applied to the piezoelectric element 331 in the positive direction in the piezo actuator shown in FIG. 6A, the length of the piezoelectric element 331 is reduced and the voltage is applied in the opposite direction to the piezoelectric element 332 attached below. Give it a length. Since the piezoelectric elements 331 and 332 are bonded to each other, the piezo actuator is bent toward the piezoelectric element 331 having a reduced length. On the contrary, when the voltage is applied in the piezo actuator shown in FIG. 6A in the reverse direction to the piezoelectric element 331, the length of the piezoelectric element 331 is increased and the voltage is applied in the positive direction to the piezoelectric element 332 attached below. If you walk, the length will be reduced. Also, since the piezoelectric elements 331 and 332 are bonded to each other, the piezo actuator is bent toward the piezoelectric element 332 having a reduced length. In this manner, when the voltage is applied to each of the overlapping piezoelectric elements 331 and 332 of the piezo actuators 317 to 326 in different directions, the piezo actuators 317 to 326 are as shown in FIG. 6B or 6C. Causes deformation in form. In general, piezo actuators have a small time constant (i.e. a fast reaction rate), can exert a large force relative to mass, and provide precise control. A predetermined number of piezo actuators 317 to 326 are attached to the upper flip 311, the lower flip 312, the upper diaphragm 313, and the lower diaphragm 314 to drive the compression means 310.

7A to 7G are diagrams illustrating the operating principle of the compression means 310 according to the present invention in the order of operation.

In the stationary state shown in FIG. 7A, the discharge valve 311 and the suction valve 312 of the compression means 310 are closed. In the opening step of the suction valve 312 shown in FIG. 7B, the upper and lower diaphragms 313 and 314 simultaneously recess the center portion thereof, and at the same time, the suction valve 312 is slightly opened to reduce the volume of the pressure chamber 327. Reduce and let some of the refrigerant inside the suction port 328. In the refrigerant suction step shown in FIG. 7C, the center portion of the upper diaphragm 313 is inflated outward with the discharge valve 311 closed, and at the same time, the lower diaphragm 314 is opened with the suction valve 312 largely opened. The middle part bulges outward. At this time, the pressure in the pressure chamber 327 is lowered to suck the refrigerant. In the closing step of the suction valve 312 illustrated in FIG. 7D, the suction valve 312 is closed while the refrigerant is sucked into the pressure chamber 327. In the refrigerant compressing step illustrated in FIG. 7E, the middle portion of the upper and lower diaphragms 313 and 314 is recessed inward while the suction valve 312 and the discharge valve 311 are closed, and the refrigerant in the pressure chamber 327 Is compressed. In the opening step of the discharge valve 311 illustrated in FIG. 7F, the upper and lower diaphragms 313 and 314 are recessed to open the discharge valve 311 only in the compressed state of the refrigerant in the pressure chamber 327. To be discharged. After discharging the refrigerant, both the intake valve and the discharge valve as shown in FIG. 7G are closed and return to the state shown in FIG. 7A to complete one cycle of operation of the compression means.

Compressor 300 having a plurality of compression means 310 of the first embodiment according to the present invention has a relatively simple structure, by using the piezo actuators (317 to 326) that is easy to control and quick response to the drive means The diameter of the compressor is 10mm, the diameter of the compression means has the advantage that it is easy to produce a small size within 2mm. These advantages can be used in micro machines such as active micro coolers.

8a to 8c show a second embodiment of the compression means 340 according to the invention.

As shown in FIGS. 8A to 8C, the compression means 340 of the second embodiment has diaphragms 313 and 314 attached to upper and lower portions of the circular plate 315, respectively, and on the diaphragm 313 and 314, respectively. A pair of flips is provided. The pair of flips 341 and 342 provided on the upper diaphragm 313 operate as a discharge valve, and the pair of flips 343 and 344 provided on the lower diaphragm 314 operate as a suction valve. do. The portion where the pair of flips 341 and 342 face each other is an outlet 346, and the portion where the pair of flips 343 and 344 face each other is an inlet 345.

The upper and lower diaphragms 313 and 314, the discharge valve and the suction valve composed of flips are driven by a piezo actuator as in the first embodiment.

The large arrow shown in FIG. 8C indicates the direction in which the refrigerant flows, and the small arrow indicates the direction in which the flip valves 341 to 344 constituting the discharge valve and the suction valve open and close.

Similarly to the compression means 310 of the first embodiment, the compression means 340 of the second embodiment also closes all the flip valves in a stationary state, and in turn opens the suction valve, refrigerant suction, suction valve closing, refrigerant compression, and discharge valve opening. It will work in the order of.

In the case of using a pair of flip valves as in the compression means 340 of the second embodiment, the rate at which the volume of the pressure chamber changes when the refrigerant is compressed in the refrigerant suction state without increasing the overall size of the compression means. There is an advantage that can increase the compression ratio determined by. That is, the change of the volume of the pressure chamber by the upper and lower diaphragms 313 and 314 and the flip valves 341 to 344 may be larger than when the flip valves are used one by one.

9 is a perspective view of a condenser 400 according to the present invention.

As shown in FIG. 9, the condenser 400 has a predetermined number of channel connecting portions 402 formed therein to allow the evaporated refrigerant to flow into the condenser, and is composed of a plate-shaped member having a wall around it. The through hole 403 through which the condensed refrigerant moves in the evaporator 100 direction is formed.

In the case of the condenser 400, as in the case of the evaporator, an empty space may be located on the plate-like member constituting the condenser 400, the heat transfer promoting means as shown in Figure 2b to 2f is provided May be

The condenser 400 may be manufactured in large quantities by micro molding using a mold manufactured by a semiconductor process, a LIGA process, or a micro discharge process.

10 is a P-h diagram illustrating the operation of an active micro cooler according to the present invention.

As shown in Figure 10, the refrigerant is evaporated by the heat of the heat source in the evaporator 100 (① → ②). The evaporated refrigerant flows through the channel connection part 102 of the evaporator 100 to the channel connection part 304 provided under the compression means 310 of the compressor 300. Here it is sucked into the compressor 300 and is compressed (② → ③). The compressed refrigerant flows to the condenser 400 through the channel connecting portion 304 provided on the compressor 300. The evaporated refrigerant introduced into the condenser through the channel connection part 402 of the condenser releases heat from the condenser to the high temperature part of the cooler and condenses to become a liquid state (③ → ④). The condensed refrigerant has a through hole 403 located at the center of the condenser 400, a through hole 302 located at the center of the compressor 300, and a through hole 202 located at the center of the heat insulating plate 200. It is introduced into the evaporator 100 through a conduit formed to be connected. An expansion valve is provided on the conduit, and the refrigerant condensed before entering the evaporator 100 is lowered while passing through the expansion valve (④ → ①).

As described above, the present invention proposes an active micro cooler having a relatively simple structure and having a large cooling capacity and easy to manufacture.

The active micro cooler according to the present invention has a relatively simple structure and a large cooling capacity compared to the passive micro cooler. In addition, the piezo actuator is very easy to control by the driving means, precise operation is possible, and the time constant is small. The active micro cooler has a total diameter of about 10 mm and a height of about 5 mm. Even if it is made as small as possible, it is possible to operate finely.

In the above, certain preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. .

1A is a perspective view of a notebook computer equipped with an active micro cooler according to the present invention.

1b is a state diagram of use of an active micro cooler according to the present invention;

1C is an exploded perspective view of an active micro cooler according to the present invention.

2a to 2f are perspective views of an embodiment of an evaporator of an active micro cooler according to the invention;

Figure 3 is a perspective view showing a heat insulating plate of the active micro cooler according to the present invention.

4 is a perspective view of a compressor of an active micro cooler according to the present invention;

Fig. 5A is a plan perspective view showing a first embodiment of the compression means constituting the compressor of the active micro cooler according to the present invention.

Fig. 5B is a rear perspective view showing a first embodiment of the compression means constituting the compressor of the active micro cooler according to the present invention.

Fig. 5C is a sectional perspective view showing a first embodiment of the compression means constituting the compressor of the active micro cooler according to the present invention.

6a to 6c are diagrams for explaining the principle of operation of a piezo actuator used as a driving means of a compressor of an active micro cooler according to the present invention;

7a to 7g are views showing the operation sequence of the compression means constituting the compressor of the active micro cooler in the present invention.

8A is a plan perspective view showing a second embodiment of the compression means constituting the compressor of the active micro cooler according to the present invention;

8B is a rear perspective view showing a second embodiment of the compression means constituting the compressor of the active micro cooler according to the present invention;

8C is a sectional perspective view showing a second embodiment of the compression means constituting the compressor of the active micro cooler according to the present invention;

9 is a perspective view of a condenser of an active micro cooler according to the present invention;

10 is a P-h diagram showing the operation of an active micro cooler according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: notebook computer 10: active micro cooler

20: heat pipe 30: MPU chip

40: heat spreader 100: evaporator

101: heat transfer promoting means 102: channel connection

105: pin 200: heat insulation plate

201: channel connecting portion 202: through hole

300: compressor 302: through hole

303: channel connection 304: receiving groove

310: compression means 311: discharge valve

312: suction valve 313: upper diaphragm

314: lower diaphragm 315: circular plate

316: outlets 317 to 326: piezo actuators

327: pressure chamber 328: inlet

331 and 332: piezoelectric element 340: compression means

341 to 344: flip valve 345: inlet

346: outlet 400: condenser

402: channel 403: through hole

Claims (8)

delete delete An evaporator attached directly to the heat source to vaporize the refrigerant; A compressor for sucking and compressing the refrigerant gas vaporized in the evaporator; A condenser dissipating heat from the refrigerant while condensing the refrigerant gas compressed in the compressor; A conduit to allow refrigerant condensed in the condenser to enter the evaporator; And An expansion valve provided on the conduit to expand the condensed refrigerant; The evaporator is provided with heat transfer enhancing means on a plate-shaped member having a wall around the periphery, and an active micro cooler, characterized in that a predetermined number of channel connections are formed to allow the evaporated refrigerant to move to the compressor. An evaporator attached directly to the heat source to vaporize the refrigerant; A compressor for sucking and compressing the refrigerant gas vaporized in the evaporator; A condenser dissipating heat from the refrigerant while condensing the refrigerant gas compressed in the compressor; A conduit to allow refrigerant condensed in the condenser to enter the evaporator; And An expansion valve provided on the conduit to expand the condensed refrigerant; In the compressor, a predetermined number of compression means are symmetrically disposed on the plate member to compress the refrigerant under the plate member to be discharged to the upper side of the plate member, and the refrigerant condensed in the condenser may move in the direction of the evaporator. An active micro cooler characterized in that a hole is formed. The method of claim 4, wherein the compression means, A pressure chamber provided therein; A diaphragm constituting an outer wall of the pressure chamber and capable of changing the volume of the pressure chamber by deformation; A suction valve capable of opening and closing the refrigerant to suck the refrigerant into the pressure chamber; A discharge valve which can be opened and closed to discharge the refrigerant from the pressure chamber; And And a channel through which compressed refrigerant can move in the condenser direction. The vibration plate of claim 5, wherein the diaphragm is driven by a predetermined number of piezo actuators symmetrically disposed on the diaphragm, And the suction valve and the discharge valve are driven by piezo actuators respectively disposed on the suction valve and the discharge valve. An evaporator attached directly to the heat source to vaporize the refrigerant; A compressor for sucking and compressing the refrigerant gas vaporized in the evaporator; A condenser dissipating heat from the refrigerant while condensing the refrigerant gas compressed in the compressor; A conduit to allow refrigerant condensed in the condenser to enter the evaporator; And An expansion valve provided on the conduit to expand the condensed refrigerant; The condenser is provided with a predetermined number of channel connections for allowing the evaporated refrigerant to flow into the condenser, and is formed of a plate-shaped member having a wall around it, and is provided with heat transfer enhancing means on the plate-like member. An active micro cooler, characterized in that the through-hole is formed that can move in the direction of the evaporator. The active micro cooler of claim 4, wherein the conduit is connected to a through hole formed in the compressor or the condenser.