JP2009154111A - Piezoelectric pump, cooling device, and electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric pump excellent in the connection reliability of an electrode formed in a piezoelectric body and wiring and easy to be built in, a cooling device, and an electronic appliance. <P>SOLUTION: Since wiring 41 for voltage application to an electrode 38 is connected corresponding to a position at which the vibration of a piezoelectric element 37 or the like forms a node P when the piezoelectric element 37 or the like is operated, even if the piezoelectric element 37 is operated and a diaphragm 36 is vibrated, the position where the wiring 41 is connected to the electrode 38 is scarcely fluctuated and thus the load on the connection point of the wiring 41 and the electrode 38 can be lowered and reliability of the connection can be improved. Since the piezoelectric pump main body 31 and an operation circuit substrate 32 are integrally connected, a drive circuit is not required to install in a portable type video camera 1 side separately from the piezoelectric pump main body 31, and thus a load of designing the operation circuit can be lessened and the cooling device 16 can be built in the portable type video camera 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a piezoelectric pump, a cooling device, and an electronic device used for cooling a hard disk drive or the like mounted on a portable electronic device such as a portable video camera.

  Conventionally, as a technique for cooling an electronic component mounted on a portable electronic device, for example, a diaphragm is vibrated in a chamber having a nozzle for ejecting gas, and a gas for cooling is ejected from the nozzle. A "jet generator" is disclosed (Patent Document 1).

  In addition, when generating a sound by vibrating the diaphragm using the piezoelectric action, the reliability of the connection at the connection point between the wiring for applying a voltage to the piezoelectric body and the electrode provided on the piezoelectric body There was a problem that decreased.

In order to solve this problem, a technique for connecting an electrode provided on a piezoelectric body to a flexible conductor is disclosed (Patent Document 2).
JP 2006-297295 A (paragraphs [0029] to [0031], FIG. 2) Japanese Utility Model Publication No. 59-33396 (page 3, lines 3-8, FIGS. 3, 4)

  However, in the technique of the above-mentioned Patent Document 2, the flexible conductor connected to the electrode provided on the piezoelectric body vibrates when the piezoelectric is driven. Therefore, the wiring for applying a voltage to the piezoelectric body and the piezoelectric body are provided. There is a problem that it is difficult to ensure the reliability of the connection because a load is applied to the connection portion with the electrode and the flexible conductive wire.

  In the technique disclosed in Patent Document 1, since the piezoelectric pump (cooling device) having a piezoelectric body and the drive circuit board that drives the piezoelectric pump are separately configured, the drive circuit board must be incorporated on the electronic device side. As a result, a load is imposed on the design of the drive circuit, and as a result, there is a problem that it is difficult to easily incorporate the piezoelectric pump into the electronic device.

  In view of the circumstances as described above, an object of the present invention is to provide a piezoelectric pump, a cooling device, and an electronic device that are excellent in connection reliability between electrodes and wiring provided on a piezoelectric body and can be easily assembled.

  In order to solve such a problem, a piezoelectric pump according to the present invention includes a hole for introducing a fluid from the outside into the inside and ejecting the fluid from the inside, and a wall portion disposed so as to face the hole. A pump body having a piezoelectric body provided on the wall to vibrate the wall, an electrode provided outside the piezoelectric body, a driving circuit for driving the piezoelectric body, and the piezoelectric body A drive circuit board integrally connected to the pump body, and a voltage application wiring connected to the electrode corresponding to a position that becomes a vibration node of the piezoelectric body when It comprises.

  In the present invention, since the voltage applying wiring is connected to the electrode corresponding to the position of the vibration of the piezoelectric body when the piezoelectric body is driven, the piezoelectric body is driven and the wall portion of the pump body The position where the voltage applying wiring is connected to the electrode hardly fluctuates even if the vibration occurs, and the load applied to the connecting portion between the voltage applying wiring and the electrode can be reduced to improve the connection reliability. In addition, since the pump body and the drive circuit board are integrally connected, there is no need to incorporate the drive circuit on the electronic device side separately from the pump body, and the design burden of the drive circuit can be reduced. The pump can be easily incorporated into electronic equipment.

  The drive circuit includes an AC oscillator, a transformer having a primary winding connected to the AC oscillator, and a secondary winding through which current flows by electromagnetic action from the primary winding, and in parallel with the secondary winding. And an electronic variable reactance element connected thereto. The electronic variable reactance element includes, for example, a variable capacitor and a variable coil.

  Thus, the piezoelectric body can be driven via the transformer based on the frequency from the AC oscillator, and the piezoelectric body can be driven by changing the energy stored in the electronic variable reactance element by the electronic variable reactance element, for example. The frequency can be controlled.

  It is preferable that the drive circuit board is a flexible board, and the voltage application wiring is provided on the flexible board.

  As a result, even when the position where the voltage application wiring is connected to the electrode of the piezoelectric body fluctuates during driving of the piezoelectric body, the flexible substrate is bent and a load is applied to the connection place between the voltage application wiring and the electrode. It can reduce and can prevent the fracture | rupture in this connection location.

  The voltage application wiring and the electrode are preferably connected at a plurality of locations. Thereby, the connection reliability between the voltage application wiring and the electrode can be further improved.

  A piezoelectric pump according to the present invention introduces a fluid from the outside into the interior and ejects the fluid from the inside, a wall portion arranged to face the hole, and vibrates the wall portion Therefore, when the piezoelectric body is driven, a pump body having a piezoelectric body provided on the wall and an electrode provided on the outside of the piezoelectric body, a drive circuit for driving the piezoelectric body, and A housing having a voltage application wiring connected to the electrode corresponding to a position serving as a node of vibration of the piezoelectric body, and integrally fixed to the pump body.

  In the present invention, since the voltage applying wiring is connected to the electrode corresponding to the position of the vibration of the piezoelectric body when the piezoelectric body is driven, the piezoelectric body is driven and the wall portion of the pump body The position where the voltage applying wiring is connected to the electrode hardly fluctuates even if the vibration occurs, and the load applied to the connecting portion between the voltage applying wiring and the electrode can be reduced to improve the connection reliability. In addition, since the pump body and the housing are integrally fixed, it is not necessary to incorporate a drive circuit on the electronic device side separately from the pump body, and the burden of designing the drive circuit can be reduced. It can be easily incorporated into electronic equipment.

  The cooling device according to the present invention includes a fluid introducing portion having a passage for introducing a fluid from the outside, a hole for introducing the fluid into the inside from the passage and ejecting the fluid from the inside, and the hole A pump body having a wall portion disposed so as to oppose, a piezoelectric body provided on the wall portion to vibrate the wall portion, and an electrode provided on the outside of the piezoelectric body; and the piezoelectric body And a voltage application wiring connected to the electrode corresponding to a position that becomes a vibration node of the piezoelectric body when the piezoelectric body is driven, and the pump body And a drive circuit board integrally connected thereto.

  The fluid introduction part preferably has a discharge port provided so as to face the hole with the passage interposed therebetween.

  Thus, by configuring the venturi nozzle with the hole and the discharge port, it is possible to increase the flow rate due to the “breathing operation” of the piezoelectric pump. As a result, the performance as a piezoelectric pump can be improved. In addition, it contributes to thinning.

  An electronic apparatus according to the present invention introduces a fluid from the outside into the interior and ejects the fluid from the inside, a wall portion disposed so as to face the hole, and vibrates the wall portion Therefore, when the piezoelectric body is driven, a pump body having a piezoelectric body provided on the wall and an electrode provided on the outside of the piezoelectric body, a drive circuit for driving the piezoelectric body, and A piezoelectric pump having a voltage application wiring connected to the electrode corresponding to a position of a vibration node of the piezoelectric body, and a drive circuit board integrally connected to the pump body; And an electronic component that is cooled based on the fluid ejected from the piezoelectric pump.

  The piezoelectric pump is also used as a speaker of the electronic device. Thereby, the speaker excellent in the connection reliability of the voltage application wiring and the electrode can be obtained.

  As described above, according to the present invention, it is possible to provide a piezoelectric pump that is excellent in connection reliability between an electrode provided on a piezoelectric body and wiring and can be easily assembled.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of a main part showing a configuration of a portable electronic device according to an embodiment of the present invention, FIG. 2 is a sectional view including a microphone and a lens of the portable electronic device, and FIG. It is an external view. Here, a portable video camera is taken as an example of the portable electronic device, but a portable phone or other electronic device may of course be used.

  As shown in these drawings, in the portable video camera 1, the captured subject video is recorded / reproduced by the HDD unit 5 mounted in the housing 3 of the camera body 2.

  As shown in FIG. 3, the portable video camera 1 has a display 4 such as a lens 4 of a camera unit, a microphone 6 for collecting sound at the time of imaging, and an LCD or the like that is pivotally attached to the camera body 2 and serves as a monitor and finder. Unit 7, eyepiece 8, and operation button group 9, and a cooling device 16 is disposed on the bottom 10 of the housing 3.

  The casing 5a of the HDD unit 5 is a metal part cast on the front side (the back side in FIG. 1) by aluminum die casting or the like, and the back side (the front side in FIG. 1) is composed of a printed circuit board for driving. The metal portion is on the lower side and is bonded to the heat transfer section 20 made of a metal such as copper having high thermal conductivity through the heat conductive sheet 21a.

  The heat transfer unit 20 has a shape in which both ends of the strip-shaped copper plate are bent in opposite directions to each other, and a heat transfer sheet 21 a is joined to one bent piece 20 a and fixed to the HDD unit 5. The heat transfer sheet 21b is also joined to the other bent piece 20b, and the heat conductive sheet 21b is joined to the upper surface of the sealed casing 19, and the HDD unit 5 is fixed on the sealed casing 19 as shown in FIG.

  The sealed casing 19 and the cooling device 16 are fixed to the bottom 10 of the housing 3 via screws 23. Accordingly, the heat heated to a high temperature by the HDD unit 5 is transmitted to the heat transfer unit 20, and this heat is cooled by the cooling device 16.

FIG. 4 is a perspective view of the cooling device 16.
As shown in FIG. 4, the cooling device 16 includes a piezoelectric pump main body 31 and a drive circuit board 32 integrally connected to the piezoelectric pump main body 31.

  The piezoelectric pump main body 31 is formed with a discharge hole 33 for ejecting a gas substantially at the center. Holes 34 serving as gas passages are formed at the four corners of the piezoelectric pump body 31. On the drive circuit board 32, a microtransformer 35 and the like constituting a part of a drive circuit for driving the piezoelectric pump main body 31 are mounted.

5 is a perspective view of the bottom side of the cooling device 16, FIG. 6 is an enlarged plan view and a perspective view showing a connection portion between the electrode formed on the piezoelectric element and the annular connection portion, and FIG. It is sectional drawing.
As shown in FIG. 5, an opening 61 is formed on the bottom surface of the piezoelectric pump main body 31, and a diaphragm 36 described later is exposed. An electrode 38 is provided on the diaphragm 36 via a piezoelectric element 37.

  From the drive circuit board 32, the annular connection part 39 is led out via the lead-out part 39d, and the wiring 41 is routed around the annular connection part 39 and the like. The annular connecting portion 39 (wiring 41) is connected to the surface of the electrode 38 at a plurality of locations by, for example, solder 40 or the like.

  As shown in FIG. 6, with respect to the diameter L1 of the piezoelectric element 37 and the electrode 38, the position of the solder 40 is provided on the circumference of the diameter L2. The circumference of the diameter L2 is a position corresponding to a vibration node of the piezoelectric element 37 when the piezoelectric element 37 is driven, for example, as will be described later. Connection points of the plurality of solders 40 are provided at equal intervals in the circumferential direction of the annular connection part 39.

  As shown in FIG. 7, for example, a metal plate having the same shape as the piezoelectric element 37 is used for the electrode 38. A through hole is formed in the drive circuit board 32, and the electrode 38 and the wiring 41 (annular connection portion 39) are connected by the solder 40 in the through hole.

FIG. 8 is a cross-sectional view showing the configuration of the cooling device 16, and FIG. 9 is an exploded perspective view of the piezoelectric pump body 31.
As shown in FIG. 8, the cooling device 16 includes a piezoelectric pump main body 31 and a drive circuit board 32 integrally connected to the piezoelectric pump main body 31.

  As shown in FIG. 8, the piezoelectric pump body 31 includes, in order from the top, a top plate 43, an insertion plate 44 for forming the passage 42, a top plate 45 for the pump chamber, and a medium for forming a space in the pump chamber. An insertion plate 46, a diaphragm 36 as a wall portion, a piezoelectric element 37 attached to the back surface of the diaphragm 36, an electrode 38, a protective ring 47, and a ring 47B.

  As shown in FIG. 9, the top plate 43 has, for example, a substantially box shape, and a discharge hole 33 for discharging the gas ejected from the pump chamber toward the bent piece 20 b in the center of the top plate 43. Is provided.

  The insertion plate 44 has a substantially rectangular shape, for example, and has a cross-shaped punching portion 48 in order to form the passage 42. The venturi nozzle part is provided at a position corresponding to the discharge hole 33, that is, at the center of the insertion plate 44 (intersection of the cross-shaped punching part 48).

  The top plate 45 of the pump chamber has, for example, a square shape, and a hole 50 or the like is formed at each corner to form a passage 42. The top plate 45 is provided with a hole 53 for introducing the gas from the passage 42 into the pump chamber and for ejecting the gas from the pump chamber through the discharge hole 33 to the bent piece 20 b side.

  In the insertion plate 46 for forming the space in the pump chamber, a hole 55 for forming the space in the pump chamber is formed in the center, and holes 56 are formed in four corners to form the passage 42. The insertion plate 46 has a thickness for forming a space to some extent as a pump chamber.

  The diaphragm 36 also has the same shape as the top plate 45 described above, and a hole 57 is formed at each corner to form a passage 42.

  The piezoelectric element 37 has a circular shape, for example, and vibrates according to an applied voltage (alternating voltage). For the piezoelectric element 37, for example, a piezoelectric material such as lead zirconate titanate (PZT) is used.

  The protection ring 47 has the same shape as the above-described insertion plate 46 and the like, and a hole 58 is formed at each corner to form the passage 42.

  For example, a metal plate having the same shape as the piezoelectric element is used for the electrode 38. Instead of the electrode 38, a silver paste may be applied to the surface of the piezoelectric element 37 to form an electrode.

  The ring 47B has the same shape as the protective ring 47, and a notch 60 is formed inside each hole 59 at each corner. The height of the protective ring 47 and the ring 47B is a thickness that prevents the diaphragm 36, the piezoelectric element 37, and the annular connection part 39 from colliding with the bottom 10 of the housing 3 during the vibration due to the vibration of the piezoelectric element 37. Have

FIG. 10 is a block diagram showing a schematic configuration of a control system of the piezoelectric element 37, and FIG. 11 is a diagram showing a circuit on the piezoelectric element 37 side.
The control system 100 of the piezoelectric element 37 includes a drive circuit 35A, a microtransformer 35, a variable capacitor 79, a diaphragm 36, a piezoelectric element 37, and an electrode 38.

  The drive circuit 35A includes an oscillator (OSC) 70, a DIV circuit 72, a counter circuit 73, a DAC (digital / analog converter) 74, a VCO (voltage controlled oscillator) 75, FETs 76 and 77, a power control circuit 81, and a voltage control circuit 82. An AND circuit 83, a DIV circuit 84, a counter circuit 85, a DAC 86, and a BUF (amplifier) 87.

  A clock pulse signal of a predetermined frequency oscillated from the oscillator 70 is input to a DIV circuit (frequency divider circuit) 72, where it is divided by a predetermined frequency division ratio and input to a counter circuit 73. The counter circuit 73 counts the output pulses of the DIV circuit (frequency divider circuit) 72 and inputs the count result to a DAC (digital / analog converter) 74. The DAC 74 converts the count value into an analog signal and outputs the analog signal to the VCO 75.

  The two output terminals of the VCO 75 are connected to the gates of the FETs 76 and 77, respectively, and the drains of the FETs 76 and 77 are connected to both ends of the primary coil 35a of the microtransformer. The VCO 75 switches the FETs 76 and 77 on and off at a frequency corresponding to the control voltage from the DAC 74. Thereby, the frequency of the alternating current flowing through the primary coil 35a of the microtransformer is controlled.

  A diaphragm 36 for driving the piezoelectric element 37 is connected in series to one end of the secondary coil 35b of the microtransformer 35, and an electrode 38 is connected in series to the other end of the secondary coil 35b. Yes. A piezoelectric element 37 is disposed between the diaphragm 36 and the electrode 38.

  The voltage control circuit 82 detects the voltage at the points A and B of the secondary circuit, and variably controls the capacitance of the variable capacitor 79 based on the detected voltage. More specifically, the voltage control circuit 82 switches the logical value input to the AND circuit 83.

  The input terminal of the AND circuit 83 is connected to the output of the oscillator 70 together with the control output of the voltage control circuit 82. The control output of the voltage control circuit 82 is an output in which the ratio of the time of H (logical value) and the time of L (logical value) is varied according to the target control amount. As a result, the clock pulse signal corresponding to the control output of the voltage control circuit 82 is input to the DIV circuit 84. The clock pulse signal input to the DIV circuit 84 is divided by the DIV circuit 84 at a predetermined frequency dividing ratio and input to the counter circuit 85. The counter circuit 85 counts the output pulses of the DIV circuit 84 and inputs the count result to the DAC 86. The DAC 86 converts the count value into an analog signal and outputs the analog signal to the BUF (amplifier) 87. The BUF (amplifier) 87 amplifies the signal from the DAC 86 and outputs the amplified signal to the variable capacitor 79.

  The power control circuit 81 outputs a signal for controlling the duty to the VCO 75.

  As shown in FIG. 11, the circuit on the piezoelectric element 37 side has a configuration in which a secondary coil 35b, a diaphragm 36, and an electrode 38 are connected in series, and a variable capacitor 79 is connected in parallel. The other parts are not shown in FIG. The variable capacitor 79 includes input / output electrodes 79a and 79b and control electrodes 79c and 79d for controlling the capacitance by changing the dielectric constant of the variable capacitor 79. For example, the control electrode 79d is connected to the output terminal of the drive circuit 35A. A piezoelectric element 37 is disposed between the diaphragm 36 and the electrode 38.

Next, operation | movement of the cooling device 16 comprised in this way is demonstrated based on Fig.12 (a)-(e).
FIG. 12A to FIG. 12E are diagrams for explaining the operation of the cooling device 16.
In the state shown in FIG. 12A, by applying an alternating voltage to the piezoelectric element 37, the diaphragm 36 is bent and deformed as shown in FIG. 12B, and the volume of the pump chamber is increased. As a result, outside air is introduced into the passage 42 from the introduction hole 25 and taken into the pump chamber through the hole 53.

  As shown in FIGS. 12C and 12D, the diaphragm 36 is bent and deformed to reduce the volume of the pump chamber. Thereby, air in the pump chamber is ejected from the discharge hole 33 through the hole 53. At this time, air in the passage 42 is simultaneously ejected from the discharge hole 33 by the venturi nozzle constituted by the hole 53 and the discharge hole 33 to increase the flow rate. As a result, air is blown onto the sealed casing 19 shown in FIG. 2 to cool the HDD unit 5 via the heat transfer unit 20.

  As shown in FIG. 12 (e), the diaphragm 36 is bent and deformed, and the volume of the pump chamber is increased again. Thereby, outside air is again taken into the pump chamber from the hole 53 through the passage 42.

  In FIG. 12, the hole 53 and the discharge hole 33 are separated. However, it may be configured by one continuous hole.

FIG. 13 is a diagram illustrating the amount of displacement of the piezoelectric element 37 when the piezoelectric element 37 is vibrating.
FIG. 13A shows a side shape of the piezoelectric element 37 when the piezoelectric element 37 is vibrating. Assuming that the reference position O is when the piezoelectric element 37 is not vibrating, the displacement amount H of the piezoelectric element 37 from the reference position O is substantially zero at the position corresponding to the vibration node P (solder 40) of the piezoelectric element 37. I understand that there is.

  As described above, according to the present embodiment, when the piezoelectric element 37 or the like is driven as shown in FIG. 13A, the electrode 38 is applied to the electrode 38 corresponding to the position of the vibration node P of the piezoelectric element 37 or the like. Since the voltage application wiring 41 is connected, even if the piezoelectric element 37 is driven and the diaphragm 36 vibrates, the position where the wiring 41 is connected to the electrode 38 hardly changes (as shown in FIG. 13). The displacement amount at the time of driving from the reference point O becomes substantially zero at the position of the node P), and the load applied to the connection portion between the wiring 41 and the electrode 38 can be reduced and the connection reliability can be improved.

  In addition, since the piezoelectric pump body 31 and the drive circuit board 32 are integrally connected, it is not necessary to incorporate a drive circuit separately from the piezoelectric pump body 31 on the portable video camera 1 side, and the design burden of the drive circuit is eliminated. The cooling device 16 can be easily incorporated into the portable video camera 1.

  The annular connection part 39 and the lead-out part 39d of the drive circuit board 32 are flexible boards. As a result, even when the position where the wiring 41 is connected to the piezoelectric element 37 fluctuates during driving of the piezoelectric element 37, the annular connection portion 39 and the lead-out portion 39 d are bent to the connection portion between the wiring 41 and the electrode 38. It is possible to reduce the load and prevent breakage at this connection point.

  Since the wiring 41 and the electrode 38 are connected at a plurality of locations, the connection reliability between the wiring 41 and the electrode 38 can be further improved.

  The drive circuit board 32 is connected in parallel to the microcoil 35 having a primary coil 35a connected to the drive circuit 35A and a secondary coil 35b through which current flows by electromagnetic action from the primary coil 35a, and the secondary coil 35b. And a variable capacitor 79.

  Accordingly, the piezoelectric element 37 can be driven via the microtransformer 35 based on the driving frequency from the VCO 75, and the energy stored in the variable capacitor 79 can be changed to control the driving frequency of the piezoelectric element 37. it can.

Next, an embodiment of the cooling device 16 will be described.
(1) Pump chamber volume (area, height)
Diameter φ16mm
Height 0.15mm
(2) Area of air introduction hole 25 from outside Diameter φ1.2 mm × 4 locations (3) Area of air outlet (discharge hole 33, hole 53)
Pump chamber hole 53 Diameter φ0.6mm
Discharge hole 33 Diameter φ0.8mm
(4) Volume (area, height) of the entire cooling device 16
Area 20mm x 20mm
1.6mm height
(The height excluding the nozzle. The nozzle height when the nozzle is provided is 0.8 mm, and the total height is 2.4 mm.)
(5) The amplitude of the piezoelectric element 37 is about ± 6 μm. (6) The vibration frequency of the piezoelectric element 37 is about 24 kHz. (7) The diameter L1 of the piezoelectric element 37.
6mm
(8) Diameter L2 (distance between solders 40) of the annular connecting portion 39
4mm
(10) The flow rate is 1.0 L / min.

  A cooling device according to another embodiment of the present invention will be described. In this embodiment and subsequent embodiments, the same components as those in the above-described embodiment will be denoted by the same reference numerals, description thereof will be omitted, and different points will be mainly described.

FIG. 14 is a perspective view of the cooling device according to the second embodiment.
Compared with the cooling device 16 of the first embodiment, the cooling device 110 of the present embodiment has, for example, a housing 120 that is integrally fixed to the protective ring 47 (or the ring 47B) instead of including the drive circuit board 32. It has. The housing 120 is provided so as to extend from the protective ring 47 (or the ring 47B) to one side, and a drive circuit, a microtransformer 35, and the like are mounted on the extending portion E. The connection between the electrode 38 and the wiring 41 by the solder 40 is the same as in the first embodiment.

  According to such a configuration, since the piezoelectric pump main body 31 and the housing 120 are fixed integrally, the cooling device 110 can be easily incorporated into the portable video camera 1.

  The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the technical idea of the present invention.

  For example, the diaphragm 36 may also be used as a speaker of the portable video camera 1. Thereby, cost reduction and size reduction can be achieved.

  In the embodiment, the electrode 38 and the wiring 41 are connected by the solder 40. However, the anisotropic conductive film ACF may be used for connection without using the solder 40.

  In the above-described embodiment, the example in which the solder 40 is provided at four locations at substantially equal intervals along the circumferential direction of the annular connection portion 39 is shown. However, the connecting portion may be formed in an annular shape similar to the shape of the annular connecting portion 39. Thereby, connection reliability can further be improved.

  In the embodiment described above, an example in which gas is ejected to cool an electronic component such as the HDD unit 5 has been described. However, the present invention is not limited to this. For example, water or the like can be ejected from the cooling device 16 to cool the electronic component.

It is a principal part disassembled perspective view which shows the structure of the portable electronic device which concerns on one Embodiment of this invention. It is sectional drawing including the microphone and lens of a portable electronic device. It is an external view of a portable electronic device. It is a perspective view of a cooling device. It is a perspective view of the bottom face side of a cooling device. It is the enlarged plan view and perspective view which show the connection location of the electrode formed in the piezoelectric element, and an annular connection part. It is AA sectional drawing of FIG. It is sectional drawing which shows the structure of a cooling device. It is a disassembled perspective view of a piezoelectric pump main body. It is a block diagram which shows schematic structure of control (drive circuit) of a piezoelectric element. It is a figure which shows the circuit by the side of a piezoelectric element. It is a figure for demonstrating operation | movement of a cooling device. It is a figure explaining the amount of displacement of a piezoelectric element when a piezoelectric element is vibrating. It is a perspective view of the cooling device of a 2nd embodiment.

Explanation of symbols

P Section 1 Portable video camera 3 Housing 5 HDD unit 16, 110 Cooling device 25 Introduction hole 31 Piezoelectric pump body 32 Drive circuit board 33 Discharge hole 34 hole 35A Drive circuit 36 Diaphragm 37 Piezoelectric element 38 Electrode 39 Toroidal connection 40 Solder 41 Wiring 42 Passage 50 Hole 70 Oscillator 35 Microtransformer 35a Primary coil 35b Secondary coil 79 Variable capacitor 120 Housing

Claims (9)

A hole for introducing a fluid from the outside into the interior and ejecting the fluid from the inside; a wall portion disposed so as to face the hole; and the wall portion for vibrating the wall portion. A pump body having a piezoelectric body and an electrode provided outside the piezoelectric body;
A drive circuit for driving the piezoelectric body; and a voltage application wiring connected to the electrode corresponding to a position that becomes a vibration node of the piezoelectric body when the piezoelectric body is driven, A piezoelectric pump comprising: a drive circuit board integrally connected to the pump body. The piezoelectric pump according to claim 1,
The drive circuit includes an AC oscillator, a transformer having a primary winding connected to the AC oscillator, and a secondary winding through which current flows by electromagnetic action from the primary winding, and in parallel with the secondary winding. A piezoelectric pump having an electronic variable reactance element connected thereto. The piezoelectric pump according to claim 1,
The drive circuit board is a flexible board, and the voltage application wiring is a piezoelectric pump provided on the flexible board. The piezoelectric pump according to claim 1,
A piezoelectric pump in which the voltage application wiring and the electrode are connected at a plurality of locations. A hole for introducing a fluid from the outside into the interior and ejecting the fluid from the inside; a wall portion disposed so as to face the hole; and the wall portion for vibrating the wall portion. A pump body having a piezoelectric body and an electrode provided outside the piezoelectric body;
A drive circuit for driving the piezoelectric body; and a voltage application wiring connected to the electrode corresponding to a position that becomes a vibration node of the piezoelectric body when the piezoelectric body is driven, A piezoelectric pump comprising: a housing integrally fixed to the pump body. A fluid introduction part having a passage for introducing fluid from the outside;
A hole for introducing a fluid from the passage into the interior and ejecting the fluid from the interior; a wall portion disposed to face the hole; and a wall portion for vibrating the wall portion A pump body having a piezoelectric body formed and an electrode provided outside the piezoelectric body;
A drive circuit for driving the piezoelectric body; and a voltage application wiring connected to the electrode corresponding to a position that becomes a vibration node of the piezoelectric body when the piezoelectric body is driven, And a drive circuit board integrally connected to the pump body. The cooling device according to claim 6,
The cooling device having a discharge port provided so that the fluid introduction portion faces the hole with the passage interposed therebetween. A hole for introducing a fluid from the outside into the interior and ejecting the fluid from the inside; a wall portion disposed so as to face the hole; and the wall portion for vibrating the wall portion. A pump body having a piezoelectric body, an electrode provided outside the piezoelectric body, a drive circuit for driving the piezoelectric body, and a vibration node of the piezoelectric body when the piezoelectric body is driven, A piezoelectric pump having a voltage application wiring connected to the electrode corresponding to the position, and a drive circuit board integrally connected to the pump body;
And an electronic component that is cooled based on the fluid ejected from the piezoelectric pump. The electronic device according to claim 8,
The piezoelectric pump is an electronic device that is also used as a speaker of the electronic device.

Images