JP2019070458A - Cooler, and electronic equipment having cooler - Google Patents

Abstract

To provide a cooler where circulation of magnetic fluid and a heat storage material are used, capable of improving heat radiation efficiency of a stored heat storage material, to shorten time necessary until being able to be used again.SOLUTION: A cooler comprises: magnetic fluid; a circulation flow passage filled with the magnetic fluid, and formed into a loop shape; a magnetic field application unit arranged in the middle of the circulation flow passage, and configured to apply a magnetic field thereto; a heat conductive unit configured to transfer heat of a heating source to the circulation flow passage containing the magnetic fluid in the vicinity of the magnetic field application unit; a heat radiation unit arranged in the middle of the circulation flow passage and at a place different from a place where the magnetic field application part is arranged, and configured to radiate heat in the circulation flow passage containing the magnetic fluid; and a heat storage body thermally connected to the heating source, and configured to receive heat transferred from the heating source, to store the heat. The heat storage body is indirectly connected to the circulation flow passage via the heating source or a heat conductive member.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a cooling device and an electronic device having the cooling device.

  2. Description of the Related Art In recent years, heat generation during operation of electronic devices has become a problem due to high performance and miniaturization of electronic devices, and various methods have been proposed as measures against heat generation.

  As one of the measures against heat generation in electronic devices, Patent Document 1 proposes a method of transporting the heat of the heat source of the electronic device to the cooling unit by circulating a magnetic fluid in a loop-shaped pipe by applying a magnetic field. There is. The magnetic fluid is warmed by the heat source to lower the magnetization, and it can be used to transport heat by circulating it by the magnetic field, and the heat is efficiently transported when the temperature of the heat source is high. Can.

  In addition, as a heat countermeasure member for preventing a rapid rise in temperature of the electronic device, a heat storage unit that stores a large amount of heat generated by the electronic device has attracted attention. As a material of such a heat storage unit, a latent heat storage material is suitable because it melts near the operating temperature of the electronic device and stores a large amount of latent heat. In Patent Document 2, there is described a method of cooling an electronic device having a configuration in which a heat storage material of a latent heat system is used in combination with the above-mentioned magnetic fluid path to thermally connect both to dissipate heat from a heat source more efficiently. It is done.

JP 2001-77571 A JP-A-2-136652

  However, in the electronic device incorporating the above-mentioned heat storage material unit as in Patent Document 2, when the cooling structure by the magnetic fluid passage is used in combination, there are the following problems.

  In an electronic device having a latent heat storage material unit, the latent heat storage material unit receives heat from a heat source and once stores latent heat, releases the amount of heat stored after the supply of heat from the heat source is stopped, and melts it. The heat storage effect can not be exhibited unless the heat storage material used is completely returned to the original solid state. In an electronic device such as a camera or the like in which the power is frequently turned on / off, the heat storage material melted by receiving heat from the heat source when the power is turned on releases the heat stored immediately after the power is turned off. It is desirable that the heat storage material unit be in a reusable state.

  Here, in the cooling method using the magnetic fluid circulation, the power of the electronic device is turned off, and when there is no heat source, no driving force is generated to flush the magnetic fluid, and the magnetic fluid can not circulate. At this time, the heat storage material does not generate driving force in the magnetic fluid flow path as a path for releasing the heat to the outside, and the heat can not be transported. As a result, the efficiency of radiating the heat stored in the heat storage material is reduced, and the time required for cooling to be reusable increases.

  The present invention has been made in view of the above problems, and in a cooling device having a cooling structure by magnetic fluid path and a cooling device having a heat storage body, and an electronic device having a cooling device, heat is suppressed by a heat storage material when the power of the electronic device is turned on. At the same time, it is possible to efficiently dissipate heat from the heat storage section by utilizing the flow path of the magnetic material when the power is turned off, to reduce the reuse time, and to improve the convenience of the user.

In order to achieve the above object, the present invention is
・ Magnetic fluid,
· A circulation channel filled with magnetic fluid and configured in a loop shape,
A magnetic field application unit for applying a magnetic field disposed in the middle of the circulation channel, and a heat conduction unit for conducting heat of a heat source to a circulation channel including magnetic fluid in the vicinity of the magnetic field application unit A heat dissipation unit disposed at a location different from the magnetic field application unit and configured to dissipate heat from the circulation channel containing a magnetic fluid;
· A heat storage body thermally connected to the heat generation source and receiving heat transferred from the heat generation source to store heat;
-The heat storage body is characterized by being indirectly connected to the circulation channel via the heat source or the heat conduction member.

  According to the present invention, when the power of the electronic device is ON, the heat storage can suppress the temperature rise of the heat source, and when the power is OFF, the heat accumulated in the heat storage can be dissipated efficiently to the outside through the magnetic material circulation channel. be able to. As a result, the time until the heat storage can be reused can be reduced, and the convenience of the user can be improved.

FIG. 1 is a schematic view showing an electronic device according to a first embodiment. The schematic diagram showing the cooling device part in a 1st Example. The schematic diagram explaining a thermal storage unit. The schematic diagram explaining the heat transport condition of the electronic device in the conventional structure. The schematic diagram explaining the heat transport condition of the electronic device in the structure of a 1st Example. The schematic diagram explaining the heat transport condition of the electronic device in the structure containing a heat insulating material.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the attached drawings. [Example 1]
An electronic apparatus having a magnetic fluid circulation cooling device according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

[1-1. Configuration of Electronic Device]
FIG. 1 shows the configuration of a projector which is an electronic device. In FIG. 1, 1 denotes a projector, 11 denotes a casing of the projector 1, 12 denotes a control board including a control unit of the projector on which circuit elements are mounted, 14 denotes a light source unit having a lamp 14a, and 13 denotes a light source unit An illumination optical system including 14; a color separation / combination optical system 15 including liquid crystal panels for R, G, and B three colors for incidence of emitted light from the illumination optical system; and 16, a color separation / combination optical system A projection lens unit projects incident light to project an image on a screen (projected surface) (not shown), 18 denotes a centrifugal fan unit, and 19 denotes a power supply unit.

  Next, the configuration of the magnetic fluid circulation cooling device in the projector 1 will be described. The reference numeral 21 denotes a circulating flow channel having a loop structure filled with magnetic fluid, 22 denotes a permanent magnet for applying a magnetic field, 23 denotes a heat conducting member for transferring the heat of the light source unit to the circulating flow channel, hatched portion 24 Shows a fin unit for dissipating the heat transported by the magnetic fluid through the circulation flow path, and 25 denotes a fan for taking in the air outside the housing 11 and sending the air to the fin unit 24. The permanent magnet 22 corresponds to the magnetic field application unit in claim 1. The fin unit 24 has a fin portion on which a large number of fins for radiating heat are erected, and a heat receiving portion for receiving the heat from the circulation flow passage 21 on the opposite surface.

  The fin unit 24 and the fan 25 are combined to form a cooling unit. The above-described 21 to 25 correspond to a magnetic fluid circulation cooling device which is a cooling device. Reference numeral 26 denotes a heat storage unit, which is connected to the light source unit 14 which is a heat source via the above-described heat conduction member 23. The heat conductive member 23 is, for example, a material having high thermal conductivity such as a carbon film.

  However, the present invention is not limited thereto, and any material that can conduct heat from a heat source is applicable to the present invention. In addition, the heat storage unit 26 and the above-described magnetic fluid circulation cooling device are not directly connected thermally but indirectly connected via the heat conducting member 23 for transferring the heat of the light source unit 14 to the circulation flow path. It shall be done. In the present embodiment, the heat storage unit 26 is thermally connected to the heat source 14 via the heat conduction member 23. However, the heat storage unit 26 may be in direct contact with the heat source 14.

  In that case, the heat storage unit 26 is thermally connected to the circulation flow path via a heat conduction member 23 which thermally connects the heat generation source 14 and the heat generation source 14 and the circulation flow path directly in contact with each other. The Rukoto. Although illustration is omitted about parts which are not the main part of the present invention in FIG. 1, a unit having other functions is also mounted in the projector 1.

  In the projector 1, light emitted from the light source unit 14 in the illumination optical system 13 is incident on the color separation / combination optical system 15. Then, the incident light passes through the color separation / combination optical system 15, and the image displayed on the liquid crystal display panel in the color separation / combination optical system 15 is projected onto the screen through the projection lens unit. The light emission control of the lamp 14 a of the illumination optical system 13 and the display control of the color separation / combination optical system 15 are performed by the control unit in the control substrate 12.

  When the projector 1 is driven, the light source unit 14 in the illumination optical system 13 and the liquid crystal panel of the color separation / combination optical system 15 become the main heat sources. The liquid crystal panel of the color separation / combination optical system 15 is cooled by the air carried through the duct as shown by the arrow from the centrifugal fan 18, and the air is sent out from the right side of the case of FIG. On the other hand, the heat of the light source unit 14 is transported and cooled by the magnetic fluid circulation cooling device.

[1-2. Configuration and operation of magnetic fluid circulation cooling device]
Next, the operation of the magnetic fluid circulation cooling device which is the main part of the present invention will be described. FIG. 2 shows only the magnetic fluid circulation cooling unit in the projector of FIG. The permanent magnet 22 is disposed in the middle of the circulation flow passage 21 and generates a magnetic field in the circulation flow passage 21. A heat conduction member 23 in contact with the light source unit 14 is disposed in the circulation flow passage 21 in the vicinity of the permanent magnet 22 so as to enclose the flow passage, and transports the heat generated by the light source unit 14. Heat the magnetic fluid. The heat conducting member 23 is preferably a metal component such as aluminum or copper having a high thermal conductivity, or a flexible graphite sheet.

  As shown in FIG. 2, the heat conducting member 23 contacts the outside of the circulation flow passage 21 in the right portion with the central line 22 a at which the polarity of the permanent magnet 22 changes. When the projector 1 is driven and the light source unit 14 irradiates and heat is generated, the magnetic fluid on the right side of the center line 22a of the permanent magnet 22 is warmed and the magnetization is reduced. In response to the force moving to the right, it starts moving in the circulation channel 21 in the direction of the arrow.

  Thus, the heat of the light source unit 14 is transported through the circulation flow path 21. The heated magnetic fluid travels in the circulation flow passage 21 in the direction of the arrow, and when it reaches the fin unit 24, heat is transmitted to the fin portion through the heat receiving portion of the fin unit 24. By driving the fan 25, air is sent to the fin portion to which the heat has been transferred, whereby cooling is performed and the temperature of the magnetic fluid is lowered. The fin unit 24 and the fan 25 correspond to the heat dissipation unit in the first aspect.

[1-3. Configuration of heat storage body]
Next, the configuration of the heat storage unit 26 will be described. The heat storage unit 26 is a unit mounted for the purpose of storing a large amount of heat exclusively inside the electronic device. FIG. 3A shows a cross-sectional view of the heat storage unit 26. The exterior cover 262 covers the periphery of the heat storage material 261, and the heat storage material sealing lid 263 seals and seals. It is desirable that the heat storage unit be made of a material having the largest possible heat capacity per unit volume, for the purpose of mounting the heat storage unit inside the electronic device.

  The heat storage material 261 used in the heat storage unit is made of a latent heat storage material, and is a material suitable for such a use. The latent heat storage material is a general term for materials whose apparent heat capacity is increased by utilizing the property of exchanging a large amount of latent heat when a substance changes in phase. Among these, a material whose melting point is higher than the normal temperature of the use environment assumed by the electronic device equipped with the heat storage unit and lower than the upper limit temperature that the electronic device can reach can be used as the heat storage material 261. That is, since the heat storage material 261 formed of the latent heat storage material deprives and stores the heat that raises the temperature of the electronic device, the temperature rise of the electronic device can be greatly delayed.

  Examples of such latent heat storage materials include organic paraffins and fatty acids, and inorganic hydrated salts. At this time, by selecting the material to be used, it is possible to adjust the phase change temperature, that is, the temperature at which the heat storage effect starts to be exhibited. In the electronic device, it is desirable to use the heat storage material to absorb the amount of heat when an excess amount of heat exceeding the cooling capacity of the device is generated. Therefore, also from this point of view, the use of a latent heat storage material capable of arbitrarily adjusting the temperature at which the heat storage effect starts to be exhibited is desirable in the present invention.

  Moreover, since a latent heat storage material melt | dissolves when exhibiting a thermal storage effect on the principle, it exhibits fluidity. Therefore, it is necessary to seal the case in a case of being mounted on an electronic device as a heat storage unit.

  In this embodiment, the case is formed of an exterior cover 262, a sealing lid 263 and the like. The heat storage material having the above-mentioned function is the latent heat type heat storage material in claim 2. In the present embodiment, as the heat storage material, the heat capacity per unit volume is large and the temperature at which the heat storage function is exhibited can be adjusted, and the latent heat storage material is taken as an example for the advantage, but it is not limited thereto. The present invention is applicable to any substance capable of storing heat.

  FIG. 3B is a schematic view of a typical electronic device mounting form of the heat storage unit 26 described above. 101 indicates an electronic device main body on which the heat storage unit 26 is mounted, and 102 indicates a housing of the electronic device 101. Reference numeral 103 denotes an electronic substrate, reference numeral 104 denotes an electronic component which is a heating element mounted on the electronic substrate 103, and reference numeral 105 denotes a heat conduction member made of aluminum sheet metal or the like.

  In the heat storage unit, as shown at 26a and 26b in FIG. 2, the surfaces 262a and 262b which are a part of the exterior cover of the heat storage unit are directly or indirectly via the heat conducting member 105 with respect to the heating element such as the electronic component 104. There is a representative example of how to prevent the temperature rise of the electronic device at an early stage by absorbing the heat by contacting with. The heat storage unit 26 is also thermally connected to the light source unit 14 corresponding to the heating element to absorb heat by the same usage as described later, thereby suppressing the temperature rise of the light source unit 14 at an early stage .

[1-4. Problems when using magnetic fluid circulation cooling device and heat storage unit in combination]
Next, problems in the case of using the magnetic fluid circulation cooling device and the heat storage unit in combination will be described, and the effects of the present invention will be described. FIG. 4 is a view showing a configuration in which the conventional magnetic fluid circulation channel cooling device and the heat storage unit are used in combination, and FIG. 4 (a) shows the flow of the magnetic fluid in the magnetic fluid circulation channel at the time of device power ON and It is the model which showed the mode of delivery of the heat from a heat source, a thermal storage unit, and a cooling fin. FIG. 4B similarly shows a state of heat transfer when the device power is turned off. The components having the same function as the magnetic fluid circulation cooling device of FIG. 2 are denoted by the same reference numerals.

[1-4-1. Heat flow at power ON]
In FIG. 4A, the heat storage unit 26 is thermally connected to the magnetic fluid circulation channel 21. At this time, when the device power is turned on, the light source lamp 14 generates heat, and the heat is transported through the heat conducting member 23, and the inside of the circulation flow path 21 as shown by the arrow α ₁ indicating heat transfer in the figure. Is transmitted to the magnetic fluid. At this time, as described above, since the magnetic fluid on the right side of the center line 22a of the permanent magnet 22 is warmed and the magnetization is reduced, the magnetic field of the permanent magnet 22 drives the driving force in the direction of arrow A going to the right. Receiving and moving the circulation channel 21 in the direction of the arrow.

Magnetic fluid warmed traveling direction of the arrow in the circulation flow path by the driving force, the cooling fin unit 24 reaches the position to be connected, externally for its heat is indicated by the arrow beta ₁ via the fin portion Released. This is the first heat radiation path. Next, when the inside of the circulation flow path is further advanced, the heat storage unit 26 is reached at the connection point. If the cooling fin unit 24 could not ferrofluid cooled sufficiently, as indicated by arrow gamma _1, heat of the surplus in the thermal storage unit 26 is transmitted.

  The heat storage unit 26 absorbs this amount of heat and this becomes a second heat radiation path, which makes it possible to delay the time for which the temperature of the electronic device rises. As described above, even if a heat quantity exceeding the cooling capacity of the cooling fin portion is transported, the heat storage unit deprives the surplus heat quantity, thereby delaying the time for which the temperature of the electronic device rises compared to the case without the heat storage unit. be able to.

  However, the heat storage unit can not be reused without releasing the amount of heat once stored. Therefore, it is desirable that the amount of heat stored when the power is turned on be promptly released from the heat storage unit to the outside of the electronic device when the power is turned off, and be in a reusable state.

[1-4-2. Heat flow when the power is off]
Here, FIG. 4 (b) shows the heat transport condition when the power is turned off in the above configuration. At this time, since the power is off, the light source lamp 14 does not function as a heat source. Therefore, the heat source in the vicinity of the permanent magnet 22 described above disappears, and a temperature difference does not occur in the magnetic fluid on the left and right of the center line 22a. Therefore, the difference in magnetization does not appear, and the driving force flowing the magnetic fluid disappears. Since there is no driving force, as shown in A 'of the figure, the magnetic fluid in the circulation flow channel does not circulate, and the heat can not be transported.

In this state, the amount of heat accumulated in the heat storage material 26 is first transmitted to the magnetic fluid immediately below as indicated by an arrow gamma _2. However, since the flow path is not circulating, the heated magnetic fluid remains near the heat storage material and can not move to the position immediately below the cooling fin portion 24, and efficient heat dissipation can not be performed. Therefore, there is a problem that much time is required to cool the heat storage material 26 until it can be reused.

[1-5. Points]
In the above-described conventional example, the heat source near the permanent magnet 22 disappears when the power is turned off, the driving force for moving the magnetic fluid in the magnetic fluid circulation channel 21 disappears, and the magnetic fluid can not circulate. It was a problem that the heat radiation efficiency from 26 fell. Therefore, in the present invention, the thermal connection state of the heat source, the magnetic fluid circulation channel, and the heat storage unit 26 is optimized, and the heat storage unit itself transmits the stored heat to the vicinity of the permanent magnet 22 when the power is off. It is characterized in that it takes a configuration that solves the above problem by functioning as an alternative to the source. The detailed explanation is given below.

  FIG. 5 is a view showing a configuration in which the magnetic fluid circulation flow path cooling device and the heat storage unit are used in combination, and FIG. 5 (a) is a flow and heat source in the magnetic fluid circulation flow path when the device power is turned on; 6 is a schematic view showing how heat is transferred from the cooling fins. FIG. 5 (b) similarly shows how heat is transferred when the device power is turned off. The components having the same function as the magnetic fluid circulation cooling device of FIG. 2 are denoted by the same reference numerals.

[1-5-1. Heat flow at power ON]
In FIG. 5A, the heat storage unit 26 is thermally connected to the light source unit 14 which is a heat source via the illustrated conductive member 23. Further, the thermal connection between the heat storage unit 26 and the above-described magnetic fluid circulation cooling device 21 is a permanent magnet which is a magnetic field application unit of the magnetic fluid circulation cooling device 21 finally via the heat conducting member 23 from the heat storage unit 26. At this time, the light source lamp 14 generates heat when the power of the apparatus is ON, and the heat is transported through the heat conducting member 23 and circulated as shown by the arrow α ₃ in the figure. It is transmitted to the magnetic fluid in the flow path 21. At this time, as described above, since the magnetic fluid on the right side of the center line 22a of the permanent magnet 22 is warmed and the magnetization is reduced, the magnetic fluid of the permanent magnet 22 receives the driving force moving to the right and the circulation flow path Start moving inside 21 in the direction of the arrow. Magnetic fluid warmed traveling direction of the arrow in the circulation flow path by the driving force, the cooling fin unit 24 reaches the position to be connected, outside its heat via the fin as indicated by the arrow beta ₃ Released.

This is the first heat radiation path. Further, with respect to the heat storage unit 26 connected to the light source lamp 14 through the heat conductive member 23, heat is transferred from the light source lamp 14 as indicated by arrow gamma _3, the temperature of the heat storage unit 26 exceeds the melting temperature of the heat storage material At this point, the heat storage material melts, and suppression of the temperature rise due to absorption of latent heat starts. From the above, due to the effect of the heat storage material, it is possible to delay the time for which the temperature of the electronic device rises, as compared to the case where the heat storage material is not provided.

[1-5-2. Heat flow when the power is off]
Here, FIG. 5 (b) shows the heat transport condition when the power is turned off in the above configuration. At this time, since the power is turned off, the light source lamp 14 does not function as a heat source. In the prior art, since the heat generation source disappears at the position of the permanent magnet portion 22, the driving force for flowing away the magnetic fluid has disappeared, but in the configuration of the present invention, the heat conducting member 23 is heat as indicated by arrow gamma ₄ through can be conducted. The important point here is that the heat is transferred from the heat storage unit 26 to the magnetic fluid circulation cooling device 21 described above so that the heat travels the above path and is finally transmitted only to a position near the permanent magnet 22. is there.

Therefore, since the heat is received and the magnetic fluid on the right side of the center line 22a of the permanent magnet 22 in the circulation flow channel 21 is warmed and the magnetization is reduced, the magnetic field of the permanent magnet 22 causes the magnetic fluid The magnetic fluid moves in the circulation channel 21 in the direction of the arrow, and reaches the point where the cooling fins 24 are connected. as shown the heat of the heat storage unit 26 due by the arrow beta _4, it can be released to the outside.

  With the above configuration, the heat storage unit 26 can generate the driving force of the magnetic flow path cooling device by replacing the role of the heat source played by the light source lamp 14 at the time of power on at the time of power off. As a result, the heat of one's own can be effectively released to the outside by using the magnetic fluid circulation path, and the time for cooling to a reusable state can be shortened.

  As described above, according to the configuration of the present embodiment, when the power of the electronic device is turned on, the heat storage can suppress the temperature rise of the heat generation source, and when the power is turned off, the heat stored in the heat storage can be efficiently It can dissipate heat well to the outside. Further, in the present invention, as shown in FIG. 6, the heat insulating material 27 is disposed between the heat storage unit 26 and the magnetic material circulation flow passage 21, and the heat storage unit 26 is not near the permanent magnet 22 in the magnetic material circulation flow passage 21. You may take the structure which suppresses transmission of the heat to a location.

  Similar to FIG. 5 (b), FIG. 6 shows the heat transport condition when the power is off in the above configuration when the power is off. When heat transfer from the heat storage unit 26 to the magnetic material circulation flow path 21 warms up the other part in the vicinity of the permanent magnet 22 due to conduction, convection, etc., the temperature difference between the left and right magnetic fluid of the center line 22a of the permanent magnet 22 decreases. , The difference in magnetization decreases. Therefore, the driving force of the magnetic fluid circulation flow path is reduced, and the heat dissipation efficiency is reduced.

Therefore, the illustration made up of such foam insulation 27 placed around the heat storage unit 26, the heat storage unit 26 and the heat to the vicinity of the permanent magnet 22 shown by an arrow gamma ₄ between the magnetic fluid circulation flow path 21 It is configured to prevent the transfer of heat to other places as indicated by the arrow γ 'other than the transfer. Thereby, the fall of heat dissipation efficiency can be prevented. The heat insulating material corresponds to the heat insulating material in claim 3.

  As described above, in the electronic device of the present invention, when the power of the electronic device is turned on, the heat storage can suppress the temperature rise of the heat source, and when the power is turned off, the heat accumulated in the heat storage can be The heat can be dissipated to the outside efficiently. As a result, the time until the heat storage can be reused can be reduced, and the convenience of the user can be improved.

  Although the projector has been described above as an example of the electronic device on which the cooling device is mounted, the invention can also be applied to other display devices, mobile phones, electronic devices that generate heat such as imaging devices, and the like.

Projector 11. Case 13. Illumination optical system 14. Light source unit 21. Circulation flow path 22. Permanent magnet 23. Heat conducting member 24. Fin unit 25. Fan 26. Heat storage unit 27. Heat insulation member

Claims (4)

Magnetic fluid,
A circulation channel filled with magnetic fluid and configured in a loop shape;
A magnetic field application unit for applying a magnetic field disposed in the middle of the circulation channel, a heat conduction unit for conducting heat of a heat source to the circulation channel including the magnetic fluid in the vicinity of the magnetic field application unit A heat dissipation unit disposed at a location different from the magnetic field application unit and configured to dissipate heat from the circulation channel containing the magnetic fluid;
A heat storage body thermally connected to the heat generation source and receiving heat transmitted from the heat generation source to store heat;
The cooling device characterized in that the heat storage body is indirectly connected to the circulation flow path via the heat generation source or the heat conduction member.   The cooling device according to claim 1, wherein the heat storage body uses a latent heat type heat storage material.   A heat insulating material is disposed between the heat storage body and the circulation flow passage, except for a thermal connection route to a position near the magnetic field application unit, to prevent heat transfer. The cooling device according to 1 or 2.   An electronic device comprising the cooling device according to any one of claims 1 to 3.