JP2000244166A - Cooling device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cooling device by which a heating part provided at an electronic apparatus is cooled with good efficiency, by a method wherein a vibration member which is held in a state of being vibrated is arranged near the heating face of a heating element, a heat absorption means is arranged near a face on the opposite side of a face adjacent to the heating element of the vibration member and a piezoelectric film is arranged on the vibration member. SOLUTION: A vibration film 7 is arranged in a state of being vibrated comparatively easily in a state of being adjacent to the surface 2a of a microprocessor 2. It is attached to a spacer 3 and a spacer 4. Then, a heat sink 8 is placed on the spacers 3, 4. By this constitution, when the microprocessor 2 generates heat, the vibration film 7 is vibrated, and the cooling operation of the microprocessor 2 is performed. As the cooling operation, in addition to a cooling operation by the heat sink, an air current due to the vibration of the vibration film 7 performs a cooling operation. As a result, a heating place can be cooled with good efficiency without a need for a motive force. In addition, since a piezoelectric film 9 is arranged on the vibration film 7, electric power can be obtained during the cooling operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device suitable for cooling a member such as a microprocessor incorporated in a personal computer, for example, and an electronic apparatus provided with the cooling device.

[0002]

2. Description of the Related Art Conventionally, a microprocessor provided in a personal computer device or the like generates a large amount of heat during operation, and is generally cooled by mounting a cooling device. For example, there is a configuration in which a fan rotated by a motor is arranged near a microprocessor, and the rotation of the fan discharges air near the microprocessor to the outside of the computer device to cool the microprocessor. is there.

[0003]

However, a cooling device using such a fan is designed to generate a flow of air almost entirely inside the device to cool the device as a whole. However, it is not suitable for use in cooling equipment in which only one or several specific places such as microprocessors generate heat at a particularly high temperature.

A conventional cooling device using a fan or the like requires electric power to rotate the fan, which causes a problem of increasing the power consumption of the computer device.

[0005] Although a microprocessor of a computer device has been described as an example, various electronic devices in which a specific portion generates heat during operation of the device have similar problems.

SUMMARY OF THE INVENTION It is an object of the present invention to efficiently cool a heat generating portion provided in an electronic device without requiring electric power or the like.

[0007]

According to the present invention, there is provided a vibrating member which is arranged near a heat generating surface of a heating element and is held in a state capable of vibrating, and a surface of the vibrating member which is close to the heat generating element has an opposite surface. And a piezoelectric film disposed on the vibrating member.

According to the present invention, when the heating element generates heat,
The heat warms the air between the heating element and the vibration member, causing the vibration member to expand and come into contact with the heat absorbing means. Here, when the vibrating member comes into contact with the heat absorbing means, the vibrating member is cooled by the heat absorbing means, and the vibrating member shrinks to come into contact with the heating element side. The repetition causes the vibration member to vibrate as long as the heating element generates heat. At this time, the piezoelectric film disposed on the vibrating member generates an electromotive force according to the amount of vibration, and by extracting the electromotive force, power can be obtained with the cooling operation of the heating element.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described.
This will be described with reference to the accompanying drawings.

In the present embodiment, an electronic apparatus having a heating element therein is provided. That is, as shown in FIG. 4, for example, an example in which the present invention is applied to a so-called desktop personal computer device 10 as an electronic device is shown. This personal computer device 10
A microprocessor 2 is arranged at a predetermined position of the circuit board 1 in the main body 11, comprising a main body 11, a display 12 and a keyboard 13.

The microprocessor 2 is one of semiconductor elements that execute necessary arithmetic processing when the personal computer device 10 is operated. The microprocessor 2 includes a heating element that generates heat at a relatively high temperature during operation. Become. Here, in the present embodiment, the members 7 and 8 constituting the cooling mechanism of the present embodiment are arranged around the microprocessor 2 to cool the microprocessor 2.

FIG. 1 is a diagram showing details of a cooling mechanism near a microprocessor 2 on a circuit board 1. Spacers 3 and 4 are arranged on the left and right sides of the place where the microprocessor 2 is arranged. The spacers 3 and 4 have a height slightly higher than the thickness of the microprocessor 2, and the vibrating membrane 7 disposed in a state of being close to the upper surface 2 a of the microprocessor 2 is supported by the spacers 5 and 6 via the support frames 5 and 6. It is attached to 3,4. That is, as shown in FIG. 2, here, the diaphragm 7 has a rectangular shape, and two opposing sides thereof are supported (held) by support frames 5 and 6, and the support frame 5 is attached to the spacer 3. At the same time, the support frame 6 is attached to the spacer 4. The mounting state is such that the diaphragm 7 can be relatively easily vibrated. The vibrating film 7 is formed of a thin film formed of a material having a relatively large expansion and contraction rate due to a change in temperature, for example.

Here, in this embodiment, as shown in FIG. 2, a piezoelectric film 9 is adhered on the vibration film 7. Here, an example is shown in which a plurality of (two in FIG. 2) piezoelectric films 9 are arranged. The piezoelectric film 9 is made of a material that generates an electromotive force by the pressure applied to the film (in this case, the vibration of the vibrating film 7), and uses a film formed of, for example, a piezo element. The configuration for extracting the electromotive force obtained by the piezoelectric film 9 will be described later.

When the vibrating film 7 on which the piezoelectric film 9 is attached is attached to the spacers 3 and 4, the upper surface 2a of the microprocessor 2 and the vibrating film 7 are arranged in a substantially parallel state. Top part 2 of microprocessor 2
The gap between a and the vibrating membrane 7 is a very close distance of about several mm so that when the vibrating membrane 7 vibrates, it comes into contact with the upper surface 2a of the microprocessor 2.

On the spacers 3 and 4, a heat sink 8 having a relatively large area is placed. The heat sink 8 is constituted by a block formed of a metal having a relatively high thermal conductivity such as aluminum. Here, the bottom surface 8a of the heat sink 8 is a flat surface, and the vibration film 7 attached to the spacers 3 and 4 and the bottom surface 8a and the vibration film 7 are also arranged substantially in parallel with each other, and the gap between them is about several mm. The distance is so close that the vibration film 7 comes into contact with the bottom surface 8a of the heat sink 8 when vibrating. On the upper surface side of the heat sink 8, for example, a large number of fins 8b for heat radiation are arranged, and the bottom surface 8a is configured to be always kept at a relatively low temperature.

Next, a circuit configuration connected to the piezoelectric film 9 adhered to the vibration film 7 will be described. FIG. 3 shows the piezoelectric film 9.
FIG. 3 is a diagram showing a circuit block connected to. As shown in FIG. 3, one electrode part and the other electrode part of each piezoelectric film 9 are
Each is connected to the input terminal of one and the other pole of the rectifier circuit 31 prepared in the computer device 10. The rectifier circuit 31 is configured by, for example, a diode bridge. The output waveform of the piezoelectric film 9 when the vibrating film 7 vibrates is an AC waveform, and the rectifying circuit 31 rectifies the AC waveform to generate a DC signal. The DC signal output from the rectifier circuit 31 is supplied to a power supply circuit 32 of the computer device 10 and used as a part of the power supply of the computer device 10. When the computer device 10 is in a state where power consumption is extremely low in a standby mode or the like, the output of the rectifier circuit 31 is supplied to power storage means (the secondary battery 33 in the example of FIG. 3) connected to the power supply circuit 32. Supply and accumulate (charge).

Next, the operation of cooling in the apparatus of this embodiment will be described with reference to FIG. When the microprocessor 2 does not generate heat, as shown in FIG. 5A, a space S between the upper surface 2a of the microprocessor 2 and the vibrating membrane 7 is formed.
1 and a space S2 between the bottom surface 8a of the heat sink 8 and the vibration film 7 are almost in the same state.

In this state, the personal computer 1
When the microprocessor 0 operates to generate heat by the operation, as shown in FIG. 5B, the air in the space S1 between the upper surface 2a of the microprocessor 2 and the vibrating membrane 7 is heated. At the same time as the diaphragm 7 expands, the diaphragm 7 itself expands due to the rise in temperature, and the diaphragm 7 is bent upward.

When the temperature further rises in the state shown in FIG. 5B, the vibration film 7 comes into contact with the bottom surface 8a of the heat sink 8, as shown in FIG. At this time, since the heat sink 8 is maintained at a relatively low temperature due to its own heat radiation effect, the vibrating film 7 and the air in the vicinity thereof are cooled, and a force acting on the vibrating film 7 acts to vibrate in the opposite direction. As a result, the vibrating membrane 7 comes into contact with the upper surface 2a of the microprocessor 2 as shown in FIG.

Then, as shown in FIG.
Is in contact with the upper surface 2a of the microprocessor 2, the diaphragm 7 and the air in the vicinity thereof are warmed, and the diaphragm 7
Expands into the states shown in FIGS. 5B and 5C. Thereafter, the heating and cooling operations of the vibrating membrane 7 and the air in the vicinity thereof are repeated, and as long as the microprocessor 2 generates heat, the vibrating membrane 7 is heated.
Starts to vibrate. Note that the vibration state (frequency of vibration, etc.) at this time depends on the material of the member forming the vibrating membrane 7,
It is determined by the film thickness and shape.

When the vibrating film 7 vibrates by performing the cooling operation as described above, an electromotive force is generated from the piezoelectric film 9 attached to the vibrating film 7. That is, as shown in FIG. 6A, an AC signal having a frequency corresponding to the vibration frequency of the vibrating film 7 is applied to the piezoelectric film 9.
Will be output from The output of the piezoelectric film 9 is rectified by the rectifier circuit 31 shown in FIG. 3 to obtain a rectified waveform as shown in FIG. 6B, and this rectified signal is supplied to the power supply circuit 32. The power supply circuit 32 can use the supplied signal as a part of the power supply, charge the secondary battery 33, and the like.

As described above, when the microprocessor 2 generates heat, the vibrating membrane 7 disposed near the microprocessor 2 vibrates, and the operation of cooling the microprocessor 2 is performed. At this time, in addition to the cooling operation by the heat sink 8, the cooling operation is also performed by the airflow generated around the microprocessor 2 by the vibration of the vibrating film 7, as in the case of driving the fan device. It is possible to efficiently cool a specific heat-generating portion such as a microprocessor without requiring a high power. In this example, since the piezoelectric film 9 is disposed on the vibrating film 7 that vibrates in accordance with the cooling operation, electric power is generated from the piezoelectric film 9 during the cooling operation, and the generated electric power is transmitted to the computer device 10. The power consumption of the computer device 10 can be reduced accordingly by making it a part of the operation power supply or charging the secondary battery.

In the above-described embodiment, the piezoelectric film 9
The power generated from the piezoelectric element 9 is used as a power source, but the temperature or amount of heat generated by the heating element (here, a microprocessor) may be estimated based on the power generated from the piezoelectric film 9. That is, for example, as shown in FIG. 7, the output of the rectifier circuit 31 for rectifying the output of the piezoelectric film 9 is
The data is supplied to a voltage detection circuit 34, and the data of the voltage value detected by the voltage detection circuit 34 is supplied to a predetermined controller 35 in the computer 10, and based on the voltage value determined by the controller 35, The calculation for estimating the heat generation temperature or the heat generation amount may be performed. By doing so, the device can determine the heat generation temperature or the heat generation amount of the heating element in the computer device 10, and for example, it becomes possible to cope with an abnormally large temperature or heat generation amount. Further, the heat generation temperature or heat amount determined by the controller 35 may be displayed on a display of a computer device.

Also, in the embodiment described so far,
Although the vibration film 7 and the piezoelectric film 9 having the shape shown in FIG. 2 are used as the vibration film that vibrates due to heat generation and the piezoelectric film disposed on the vibration film, other shapes of the vibration member and the piezoelectric member may be used.
For example, as shown in FIG. 8, the entire periphery of a rectangular vibration film 7 'is formed to be supported (held) by a support member 21, and four piezoelectric films 9' are adhered on the vibration film 7 '. The component may be arranged between the heat generating member (microprocessor) and the heat sink.

Further, as shown in FIG. 9, for example, a circular vibration film 7 ″ is prepared, and the entire periphery of the vibration film 7 ″ is made to be supported (held) by the support member 22. A structure in which a large number of piezoelectric films 9 "are adhered radially on""may be arranged between a heat generating member (microprocessor) and a heat sink.

The arrangement of the piezoelectric film on the vibrating film is not limited to these examples, but may be arranged at a position where an electromotive force can be obtained most efficiently during vibration.
The piezoelectric film may be arranged not on the upper surface of the vibration film as shown in FIGS. 2, 8 and 9 but on the lower surface of the vibration film opposite to the heating element. Alternatively, piezoelectric films may be arranged on both surfaces of the vibration film.

Further, the vibration film 7 itself may be formed of a member functioning as a piezoelectric film. By doing this,
The most efficient electromotive force is obtained with the cooling operation. Further, the vibrating film is not limited to a thin film, and may be a member having a certain thickness as the vibrating member as long as it can vibrate by heat generation and cooling.

As an example of the means for detecting the electromotive force of the piezoelectric film 7, a voltage measuring circuit is provided in the example of FIG. 7, but if it is a means for measuring the electric power proportional to the amount of heat generated as a result, Other power measuring means may be provided.

Further, as a member arranged with the heat generating member (microprocessor) and the vibration member interposed therebetween, a heat absorbing means other than the heat sink as described in the above embodiment may be used. Further, even when a heat sink is used, a configuration may be used in which a cooling airflow is caused to flow through the heat sink by a fan or the like, so that cooling may be performed more efficiently by combining with another cooling mechanism. Further, in the example shown in FIG. 4, the heat sink 8 is arranged inside the device 11, but, for example, the radiating fins of the heat sink are exposed to the outside of the device so that cooling can be performed more efficiently. You may do it.

Further, in the above-described embodiment, an example has been described in which the cooling device is a microprocessor cooling device in a desktop personal computer device. However, a computer device of another shape such as a portable personal computer device such as a notebook computer is described. If it is a device that generates heat at a particular location in the device,
Of course, it can also be used as a cooling device in various other electronic devices other than the computer device.

[0031]

According to the cooling device of the present invention, when the heating element generates heat, the vibration member vibrates due to the repetition of expansion by the heat and cooling by the heat absorbing means, and the heating element is vibrated through the vibration member. It will be cooled. At this time, the piezoelectric film arranged on the vibrating member vibrates, and an electromotive force corresponding to the vibration state is generated from the piezoelectric film, and it becomes possible to obtain electric power with the cooling operation, and a driving force is required. Not only can a specific part be cooled without performing the operation, but also power can be obtained with the cooling operation.

In this case, the provision of the power supply circuit for taking out the electromotive force generated from the piezoelectric film as a power supply makes it possible to reduce the power consumption of a device equipped with a cooling device.

Further, the provision of the measuring circuit for measuring the electromotive force generated from the piezoelectric film makes it possible to estimate the temperature or the amount of heat generated by the heating element to be cooled by the cooling device from the electromotive force.

According to the electronic device of the present invention, when the device operates to generate heat in a specific portion of the device, the expansion by the heat of the portion and the cooling by the heat absorbing means are repeated, thereby
The vibrating member comes to vibrate, and the location where heat is generated via the vibrating member is cooled. At this time, the piezoelectric film arranged on the vibrating member vibrates, and an electromotive force corresponding to the vibration state is generated from the piezoelectric film, and it becomes possible to obtain electric power with the cooling operation, and a driving force is required. Not only can a specific part be cooled without performing the above operation, but also power can be obtained in the device with the cooling operation.

In this case, since the electronic device is provided with a power supply circuit for taking out the electromotive force generated from the piezoelectric film as a power supply,
The power consumption of the device can be reduced accordingly, and the rechargeable battery built in the device can be charged.

Further, by providing a measuring circuit for measuring the electromotive force generated from the piezoelectric film, and a control means for estimating the calorific value or the temperature at the specific location based on the power measured by the measuring circuit, It becomes possible to estimate the temperature or the heat value of the heating element from the electromotive force.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overall configuration example of a cooling mechanism according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an arrangement example of a vibration film and a piezoelectric film according to one embodiment of the present invention.

FIG. 3 is a block diagram showing an example of a circuit connected to a piezoelectric film according to an embodiment of the present invention.

FIG. 4 is a perspective view showing an example of an electronic apparatus according to an embodiment of the present invention, with a part thereof cut away.

FIG. 5 is an explanatory diagram showing a cooling operation according to one embodiment of the present invention.

FIG. 6 is a waveform chart showing an example of an output waveform of a piezoelectric film according to an embodiment of the present invention.

FIG. 7 is a block diagram showing an example of a circuit connected to a piezoelectric film according to another embodiment of the present invention.

FIG. 8 is a perspective view showing an arrangement example of a vibration film and a piezoelectric film according to another embodiment of the present invention.

FIG. 9 is a perspective view showing an arrangement example of a vibration film and a piezoelectric film according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Circuit board, 2 ... Heating element, 2a ... Heating surface, 7, 7 ',
7 ″: vibrating film, 8: heat sink, 9: piezoelectric film, 10 ...
Personal computer device, 31 ... Rectifier circuit, 32 ...
Power supply circuit, 33: secondary battery, 34: voltage detection circuit, 35
…controller

Claims (6)

[Claims] 1. A vibrating member arranged near a heat generating surface of a heat generating element and held in a vibrating state, and a surface of the vibrating member close to the heat generating element is arranged near an opposite surface. A cooling device comprising: a heat absorbing means; and a piezoelectric film disposed on the vibration member. 2. The cooling device according to claim 1, further comprising a power supply circuit for extracting an electromotive force generated from the piezoelectric film as a power supply. 3. The cooling device according to claim 1, further comprising a measuring circuit for measuring an electromotive force generated from the piezoelectric film. 4. An electronic device having a specific portion that generates heat by operation of the device, wherein the vibration member is disposed near a heat generating surface of the specific portion and is held in a state capable of vibrating; An electronic device comprising: a heat absorbing means disposed on a surface adjacent to a location near an opposite surface; and a piezoelectric film disposed on the vibration member. 5. The electronic device according to claim 4, further comprising a power supply circuit for extracting an electromotive force generated from the piezoelectric film as a power source of the device. 6. The electronic device according to claim 4, wherein a measurement circuit for measuring an electromotive force generated from the piezoelectric film, and a control for estimating a calorific value or a temperature of the specific portion based on the power measured by the measurement circuit. Electronic device comprising: