Patent Application
20070029070
1. Field of the Invention
The present invention relates to a sheet type fluid circulating apparatus for circulating and transporting fluid through a plurality of fluid paths and an electronic device cooler structure using the same.
2. Background Art
Recently, electronic devices are being manufactured in a more compact and miniaturized size with more improved performance as recognized by a mobile phone and a laptop computer. Most of the semiconductors used in the electronic devices may suffer operation speed lowering or malfunction when they are heated to a temperature of a hundred and several tens Celsius degree. Since the heat generated from a central processing unit (CPU) particularly causes operation speed lowering and malfunction, the generated heat should be efficiently radiated.
The electronic components such as a semiconductor element used in an electronic circuit have different heating conditions and characteristics. Nevertheless, since the entire circuit board was cooled as a whole according to a conventional method, it was difficult to selectively cool a particular electronic component. For this reason, the cooling fan was designed based on the heating characteristic of a thermally weakest electronic component, and thus, the conventional cooling method had bad energy efficiency from the viewpoint of the entire device. In addition, the air cooling type that uses a cooling fan has bad cooling performance because the air has a low heat transfer rate. The cooling fan also increases the weight and the volume of an electronic device, so that it functions as an obstacle for manufacturing a more compact device. Furthermore, a fast rotation of the cooling fan often generates unendurable noises.
Accordingly, another cooling method has been adopted such that the heat generated from the CPU is transferred to a lower surface of the casing or a cooling panel provided in a display side through a heat pipe. However, since the conventional heat pipe is made of metal, it has a large weight, a large thickness, and little flexibility, so that it was inappropriate to use the metal pipe in a compact light-weight electronic device.
In order to solve such problems, a Japanese Patent Unexamined Publication No. 2001-165584 (hereinafter, referred to as a patent document 1) discloses a sheet type heat pipe, in which a container of the heat pipe is made of a film material other than the metal pipe.
In such a sheet type heat pipe, the fluid resistance increases when the interval between the vapor paths is reduced to obtain sufficient sheet flexibility. For this reason, the circulation flux of the working fluid is limited. Therefore, it is difficult to balance the tradeoff between the flexibility and the cooling performance.
In addition to a passive cooling device such as the heat pipe, an active cooling device in which a small driving pump is combined with a cooling sheet to more actively cool the circuit board having electronic components has been developed. However, since this method uses a large-sized pump, it is difficult to mount it in a space-limited device such as a laptop computer.
Accordingly, a Japanese Patent Unexamined Publication No. 06-264870 (hereinafter, referred to as a patent document 2) discloses a micro-pump integrated into a fluid path as a driving pump to move the fluid based on a principle of an electrostatic actuator.
In the micro-pump disclosed in the patent document 2, a silicon substrate is micro-fabricated, and an electrode is provided in a polyimide resin layer formed on the silicon substrate, so that a small quantity of fluid is controlled by the electrostatic force between the silicon substrate and the electrode. The micro-pump of the patent document 2 is not purposed to provide a cooling function. A method and a structure for filling the fluid in, for example, a fluid path of a flexible sheet and circulating it is not suggested as well as not disclosed. When the driving pump such as an electrostatic actuator is provided in the vicinity of an electronic component, the electronic component may be erroneously operated due to electromagnetic noises.
A fluid circulating apparatus according to the present invention includes: a fluid path having a closed structure provided in an inner space of a stacked flexible sheet; fluid filled in the fluid path; a fluid transport unit provided in at least a part of the fluid path of the flexible sheet to circulate the fluid in the fluid path; and a control ciruit unit for controlling the fluid transport unit.
An electronic device cooler structure according to the present invention includes: a heat generating portion having a plurality of heat generating sources; a fluid circulating apparatus for cooling a plurality of the heat generating sources; and a heatsink portion for cooling fluid in the fluid circulating apparatus, wherein at least a part of the fluid paths of the sheet type fluid circulating apparatus are connected to the heat generating sources, and a flux of the fluid flowing through the fluid path is changed based on the amount of heat generated in the heat generating sources.
The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, in which dimensions of a thickness direction, a width direction, and length direction are enlarged for convenient descriptions of a construction. In addition, like reference numerals denote like elements, and their descriptions are omitted.
Sheet type fluid circulating apparatus 1 according to a first embodiment includes a fluid path having a closed structure provided in the inner space by stacking flexible sheets 18, fluid (not shown in the drawing) moving in the fluid path, fluid transport unit 42, and a control ciruit unit (not shown in the drawing) for controlling fluid transport unit 42. The fluid path includes a plurality of cooling paths 20 and 22, heatsink path 30 provided in the inside of flexible sheet 18, inlet path 32 provided in the inside of flexible sheet 18 to connect cooling paths 20 and 22 with heatsink path 30, and outlet path 28. The fluid is filled in fluid transport unit 42, cooling paths 20 and 22, and heatsink path 30. In addition, fluid transport unit 42 has three displacement generators 34, 36, and 38 for deforming flexible sheet 18 by applying a voltage. By applying a voltage to displacement generators 34, 36, and 38 of fluid transport unit 42 using a control ciruit unit, the fluid is circulated from cooling paths 20 and 22 provided in flexible sheet 18 to heatsink path 30.
In addition, fluid transport unit 42 is provided in a part of inlet path 32 connected from heatsink path 30 to cooling path 20 and 22. Cooling path 20 is provided with diaphragm 24 in a part of inlet path 32 for compressing the flow. Also, the fluid path includes outlet path 28 connected from cooling paths 20 and 22 to heatsink path 30 and branch path 26 connected from inlet path 32 to cooling path 22.
According to the above construction, the fluid output from heatsink path 30 by fluid transport unit 42 passes through inlet path 32 and diaphragm 24, and flows through cooling path 20. In this case, the fluid heated (heat absorption) in the neighboring heat generating portions flows through outlet path 28 to heatsink path 30, cooled down (heatsink) in heatsink path 30, and is output to fluid transport unit 42 again.
Similarly, the fluid output from heatsink path 30 by fluid transport unit 42 passes through inlet path 32 and branch path 26 and flows through cooling path 22. The fluid heated in cooling path 22 passes through outlet path 28 to heatsink path 30, and then cooled down there so as to be output to fluid transport unit 42, again. The fluid is circulated by repeating these operations.
As described above, sheet type fluid circulating apparatus 1 according to a first embodiment of the present invention can efficiently cool a plurality of heat generating portions by circulating the fluid through the fluid path provided inside flexible sheet 18 using fluid transport unit 42.
In sheet type fluid circulating apparatus 1, the different flux can flow into cooling paths 20 and 22 by setting different conductance values between cooling paths 20 and 22. In the first embodiment of the present invention, a larger flux flows into cooling path 22. Therefore, the heat generating portions having different heating value can be efficiently cooled down if cooling path 22 is used for cooling a heat generating portion having a larger heating value, and cooling path 20 is used for cooling a heat generating portion having a smaller heating value.
Flexible sheet 18 is constructed by bonding sheets 12 and 14 with spacer 16. Sheets 12 and 14 and spacer 16 may be formed of resin such as polyimide resin, polyester resin, and polyethylene terephthalate resin. Spacer 16 is previously provided with the openings corresponding to cooling paths 20 and 22, heatsink path 30, inlet path 32, diaphragm 24, outlet path 28, and branch path 26, and its both surfaces are bonded with sheets 12 and 14, respectively, so that the fluid path is formed in a closed structure.
Fluid transport unit 42 uses an electrostatic force according to a first embodiment of the present invention. That is, displacement generator 34 is constructed of conductive films 33 and 40 provided in the opposite surfaces of sheets 12 and 14. Similarly, displacement generator 36 is constructed of conductive films 35 and 40 provided in the opposite surfaces of sheets 12 and 14. Similarly, displacement generator 38 is constructed of conductive films 37 and 40 provided in the opposite surfaces of sheets 12 and 14. Conductive films 33, 35, 37, 40 may be fabricated by forming an aluminum film or a copper film by, for example, a deposition method or a sputtering method.
In addition, for convenient deformation, only the areas corresponding to displacement generators 34, 36, and 38 in sheet 12 may be formed to be thinner than other areas. Similarly, sheet 14 may have thinner portions.
Although conductive film 40 provided in sheet 14 has a common connection structure by combining three displacement generators 34, 36, and 38 in this embodiment, they may be separately provided.
Water having high electric resistance is preferably used as the fluid. Alternatively, ethylene glycol can be used as the fluid. The ethylene glycol can be advantageously used even in a cold and snowy climate. In addition to water, any fluid that has low viscosity and high electric resistance can be adopted without limitation.
Although displacement generator 34 has a largest area in this embodiment, the displacement generators may have the same area.
Hereinafter, a mechanism for transporting the fluid is described with reference to
As shown in
Then, as shown in
Subsequently, as shown in
Subsequently, as shown in
By repeating the cycle including the processes shown in
Therefore, it is possible to externally radiate the heat generated in the heat generating portions from heatsink path 30 through the heatsink fins using the fluid if the heat generating portions are connected to cooling paths 20 and 22, and the heatsink fins are connected to heatsink path 30 in sheet type fluid circulating apparatus 1. In this case, since the heat transportation is performed using the fluid, it is possible to effectively radiate the heat even when the heating value of the heat generating portion is relatively large.
According to this construction, the flux of the fluid flowing to cooling paths 20 and 22 can be controlled by respective fluid transport units 42 and 62 without diaphragm 24 shown in
Similarly to sheet type fluid circulating apparatus 1 according to a first embodiment of the present invention, sheet type fluid circulating apparatus 4 according to a second embodiment includes a fluid path having a closed structure provided in the inner space of stacked flexible sheet 18, fluid (not shown in the drawing) moving through the fluid path, fluid transport unit 70, and a control ciruit unit (not shown in the drawing) for controlling fluid transport unit 70. In this embodiment, the fluid path includes a plurality of cooling paths 20 and 22, heatsink path 30 provided in the inner space of flexible sheet 18, and inlet path 32 and outlet path 28 provided in the inner space of flexible sheet 18 to connect cooling paths 20 and 22 with heatsink path 30. The fluid is filled in fluid transport unit 70, cooling paths 20 and 22, and heatsink path 30. In addition, fluid transport unit 70 has six displacement generators 72, 74, 76, 78, 80, and 82 for deforming flexible sheet 18 by applying a voltage. The fluid is circulated from cooling paths 20 and 22 provided in flexible sheet 18 to heatsink path 30 by applying a voltage to displacement generators 72, 74, 76, 78, 80, and 82 of fluid transport unit 70 using the control ciruit unit.
As shown in
According to the above construction, the fluid output from heatsink path 30 by fluid transportation unit 70 flows through inlet path 32 and diaphragm 24 to cooling path 20. The fluid heated (heat absorption) in the neighboring heat generating portions flows through outlet path 28 and heatsink path 30, and is cooled down (heat radiation) in heatsink path 30, so as to be output to fluid transport unit 70 again.
Similarly, the fluid output from heatsink path 30 by fluid transport unit 70 flows through inlet path 32 and branch path 26 to cooling path 22. The fluid heated in cooling path 22 flows through outlet path 28 to heatsink path 30, and is cooled down in heatsink path 30, so as to be output to fluid transport unit 70 again. The fluid is circulated by repeating the above processes.
Fluid transport unit 70 according to a second embodiment is constructed of a plurality of displacement generators using an electrostatic force in comparison with a first embodiment. The constructions of the displacement generators are the same as those of a first embodiment. As shown in
For convenient deformation, only the areas corresponding to displacement generators 72, 74, 76, 78, 80, and 82 of sheet 12 may have a thinner thickness than those of other areas. Alternatively, only the areas corresponding to displacement generators 72, 74, 76, 78, 80, and 82 may be formed of a material susceptible to elastic deformation. Conductive film 84 provided in sheet 14 may be commonly connected to six displacement generators 72, 74, 76, 78, 80, and 82, or individually connected to them. In a second embodiment, displacement generators 72, 74, 76, 78, 80, and 82 are commonly connected.
A mechanism for transporting the fluid of fluid transporting unit 70 in sheet type fluid circulating apparatus 4 according to a second embodiment is basically similar to that of fluid transport unit 42 in sheet type fluid circulating apparatus 1 according to a first embodiment as described with reference to
Therefore, the mechanism of fluid transport unit 70 in sheet type fluid circulating apparatus 4 according to a second embodiment will be described shortly.
Firstly, displacement generator 72 nearest to outlet path 28 is deformed to nearly close the fluid path corresponding to displacement generator 72. This deformation allows the fluid existing in the area of displacement generator 72 of heatsink path 30 to flow to both sides of displacement generator 72. Also, this deformation is generated by applying different polarity voltages to conductive films (not shown in the drawing) of sheets 12 and 14 in displacement generator 72 using the control ciruit unit. For example, when a positive voltage is applied to the conductive film of sheet 14, a negative voltage is applied to the conductive film of sheet 12. For example, when the interval between the conductive films of sheets 12 and 14 is set to 100 μm, a voltage of 100V is preferably applied.
Then, while the fluid path corresponding to displacement generator 72 is closed, a fluid path corresponding to displacement generator 74 is similarly deformed. Similarly to displacement generator 72, this deformation is generated by applying different polarity voltages to the conductive films (not shown in the drawings) of sheets 12 and 14 of displacement generator 74. The different polarity voltages generate deformation of displacement generator 74 similarly to displacement generator 72. When displacement generator 74 is deformed, since the fluid path is nearly closed by the deformation in displacement generator 72 in advance, the fluid is squeezed toward inlet path 32.
Subsequently, while the fluid path corresponding to displacement generator 74 is nearly closed, displacement generator 76 is deformed to nearly close the fluid path corresponding to displacement generator 76. Simultaneously, displacement generator 72 is restored to its initial state. In this case, similarly to displacement generator 74, different polarity voltages are applied to conductive films 75 and 84 of sheets 12 and 14 of displacement generator 76. On the other hand, the same polarity voltages are applied to the conductive films of sheets 12 and 14 of displacement generator 72. This generates a repelling electrostatic force between the conductive films of sheets 12 and 14 of displacement generator 72 to separate each other. As a result, displacement generator 72 is restored to its initial state so that the fluid path is opened. This deformation allows the fluid of displacement generator 76 to be squeezed toward inlet path 32. On the other hand, the fluid flows into the area of displacement generator 72 as shown in the arrow.
Subsequently, while the fluid path corresponding to displacement generator 76 is nearly closed, displacement generator 78 is deformed to nearly close the fluid path corresponding to displacement generator 78. Simultaneously, displacement generator 74 is restored to its initial state, and the fluid path corresponding to displacement generator 72 is closed. In this case, similarly to displacement generator 76, different polarity voltages are applied to the conductive films of sheets 12 and 14 of displacement generator 78. On the other hand, the same polarity voltages are applied to the conductive films of sheets 12 and 14 of displacement generator 74. This generates a repelling electrostatic force between the conductive films of sheets 12 and 14 of displacement generator 74 to separate each other. As a result, displacement generator 74 is restored to its initial state, and the fluid path is opened. The fluid of displacement generator 78 is squeezed toward inlet path 32. On the other hand, the fluid flows into the opened displacement generator 74, and the neighboring displacement generators 72 and 76 are closed.
Subsequently, while the fluid paths corresponding to displacement generators 72 and 78 are nearly closed, displacement generator 80 is deformed to nearly close the fluid path corresponding to displacement generator 80. Simultaneously, displacement generator 76 is restored to its initial state, and the fluid path corresponding to displacement generator 74 is closed. At this time, similarly to displacement generators 72 and 78, different polarity voltages are applied to the conductive films of sheets 12 and 14 of displacement generator 80. On the other hand, the same polarity voltages are applied to the conductive films of sheets 12 and 14 of displacement generator 76. This generates a repelling electrostatic force between the conductive films of sheets 12 and 14 of displacement generator 76 to separate each other. As a result, displacement generator 76 is restored to its initial state, and the fluid path is opened. The fluid corresponding to displacement generator 80 is squeezed toward inlet path 32. On the other hand, the fluid flows into the opened displacement generator 76.
Subsequently, while the fluid paths corresponding to displacement generators 74 and 80 are nearly closed, displacement generator 82 is deformed, and the fluid path corresponding to displacement generator 82 is nearly closed. Simultaneously, displacement generators 72 and 78 are restored to their initial states, and the fluid path corresponding to displacement generator 76 is closed. At this time, similarly to displacement generators 74 and 80, different polarity voltages are applied to the conductive films of sheets 12 and 14 of displacement generator 82. On the other hand, the same polarity voltages are applied to the conductive films of sheets 12 and 14 of displacement generators 72 and 78. This generates a repelling electrostatic force between the conductive films of sheets 12 and 14 of displacement generators 72 and 78 to separate each other. As a result, displacement generators 72 and 78 are restored to their initial states, and the fluid path is opened.
The fluid of displacement generator 82 is squeezed toward inlet path 32 as shown in the arrow. On the other hand, the fluid flows into opened displacement generators 72 and 78.
When a series of the above processes are repeated for displacement generators 72 to 82, the fluid located in heatsink path 30 is sequentially transported to inlet path 32, so that the fluid is circulated.
In addition, the voltages applied to each conductive film may have a pulse shape (e.g., a rectangular wave) or a continuously changed shape such as a sinusoidal wave.
Although sheet type fluid circulating apparatus 5 according to a third embodiment is similar to sheet type fluid circulating apparatus 3 according to a second embodiment, the constructions of fluid transport units 90 and 98 are different. Other constructions are the same as those of sheet type fluid circulating apparatus 3, and their detailed descriptions will be omitted.
As shown in
In addition, as shown in
Hereinafter, a mechanism for transporting the fluid will be described with reference to
Firstly, as shown in
Then, as shown in
Subsequently, as shown in
By repeating the above processes, the fluid flows from heatsink path 30 to inlet path 32, so that the fluid circulation is generated.
In addition, although the piezoelectric element according to this embodiment is formed of a material which expands and contracts in parallel with the fluid path, the present invention is not limited to such a construction. For example, a material which expands and contracts in a thickness direction of the piezoelectric element (across the electrodes) may be used.
According to a third embodiment of the present invention, since fluid transport units 90 and 98 include displacement generator 92 formed of a piezoelectric material and two check valves 94 and 96, the construction is simple, and a large driving force can be generated. As a result, a control ciruit unit can have a simple construction, and simultaneously, the flux of the transported fluid can be significantly increased.
In addition, if the heat generating portions are connected to cooling paths 20 and 22, and the heatsink fins are connected to heatsink path 30 using this sheet type fluid circulating apparatus, the heat generated in the heat generating portions can be output from heatsink path 30 through the heatsink fins using the fluid. The heat can be efficiently output even though amount of heat in the heat generating portions is relatively large because the heat is transported using the fluid.
In addition, although the displacement generators of the fluid transport units are operated by an electrostatic force according to first and second embodiments, the same effect can be achieved by forming the displacement generator using a piezoelectric material as described in association with a third embodiment. Furthermore, although the displacement generator of the fluid transport unit is formed of a piezoelectric material according to a third embodiment, the displacement generator may be constructed using an electrostatic force. As described above, the present invention is not limited to the constructions of the sheet type fluid circulating apparatus according to first to third embodiments, the construction of the flexible sheet and the construction of the fluid transport unit may be appropriately combined.
The electronic device cooler structure according to a fourth embodiment includes heat generating portions 110 and 112 having a plurality of heat sources, a fluid circulating apparatus for cooling a plurality of heat generating portions 110 and 112, and heatsink unit 116 for cooling the fluid of the fluid circulating apparatus. Sheet type fluid circulating apparatus 1 according to a first embodiment may be used as the fluid circulating apparatus of the electronic device cooler structure according to a fourth embodiment. At least part of cooling paths 20 and 22 of sheet type fluid circulating apparatus 1 is connected to heat generating portions 110 and 112. In addition, the fluxes flowing through cooling paths 20 and 22 are adjusted depending on the amount of heat generated in heat generating portions 110 and 112.
In this case, heatsink unit 116 is constructed of heatsink fins. The heatsink fins are connected to heatsink path 30 of sheet type fluid circulating apparatus 1. Heat generating portions 110 and 112 are electronic components mounted on circuit board 108. Specifically, the heat generating portion generating a large amount of heat may be a CPU, and the heat generating portion generating a small amount of heat may be a resistor, a capacitor, or a sensor formed of resin having low thermal resistance. Although other electronic components 114 may be additionally mounted on circuit board 108, if they do not generate heat, they are not necessary to be cooled. In this embodiment, the casing for storing circuit board 108 and sheet type fluid circulating apparatus 1 is not shown.
As shown in
For example, a temperature sensor may be provided in heat generating portion 112 such as a CPU, and the data obtained from the sensor may be processed by the control ciruit unit (not shown in the drawing) of sheet type fluid circulating apparatus 1, so that fluid transport unit 42 can be driven based on the processed data to control the flux of the cooling fluid.
Furthermore, the variation of the electric characteristic of heat generating portion 112 such as a CPU may be detected in a controller (not shown in the drawing) of the electronic device (not shown in the drawing) mounted on the circuit board, and then a signal generated based on the electric characteristic may be processed by the control ciruit unit (not shown in the drawing) of sheet type fluid circulating apparatus 1, so that the flux of the cooling fluid can be controlled by driving fluid transport unit 42 to control the variation of the electric characteristic of the heat generating portion.
The electronic device cooler structure according to the present invention is not limited to the above constructions, and the sheet type fluid circulating devices according to first to third embodiments of the present invention may be used. For example, since sheet type fluid circulating apparatus 3 has fluid transport units 42 and 62 for cooling paths 20 and 22, respectively, it is possible to reduce power consumption and individually implement an optimal cooling if each fluid transport unit 42 and 62 is individually controlled by detecting the amount of heat in heat generating portion 112 such as a CPU and the temperature of heat generating portion 110 such as a sensor which generate little heat but has small thermal resistance. In addition, in the case of sheet type fluid circulating apparatus 4 having fluid transport unit 70 in heatsink path 30, it is possible to further improve efficiency of fluid transportation by arranging fluid transport unit 70 on a flat surface of the electronic device cooler structure or the heatsink fins.
Furthermore, it is possible to actively cool the fluid by arranging an electronic cooler in addition to the heatsink fins as a heatsink unit. In this case, it is possible to effectively cool the electronic device even when a cooling under a room temperature is required. For example, a Peltier effect cooler may be used as the electronic cooler.
Moreover, if the fluid in the heatsink path is heated or cooled to a predetermined temperature, the fluid can be circulated with a constant temperature, so that it is possible to constantly maintain the temperature of a specimen even in a temperature sensitive inspection such as a DNA analysis.
Sheet type fluid circulating apparatus 210 according to a fifth embodiment of the present invention includes fluid path 215 having a closed structure provided in the inner space of stacked flexible sheet 211, fluid (not shown in the drawing) filled in fluid path 215, fluid transport units 220 and 230 provided in part of fluid path 215 of flexible sheet 211 to circulate the fluid in fluid path 215, electromagnetic shield film 212 formed in at least one surface of flexible sheet 211, a control ciruit unit (not shown in the drawing) for driving the fluid transport units, and a ground section (not shown in the drawing) for grounding electromagnetic shield film 242.
When flexible sheet 211 of sheet type fluid circulating apparatus 210 is connected to, for example, a heat generating portion of the electronic device, sheet type fluid circulating apparatus 210 is constructed such that fluid path 215 provided in fluid transport units 220 and 230 is also connected to the heat generating portion.
In this case, sheet type fluid circulating apparatus 210 uses an electrostatic force in order to drive fluid transport units 220 and 230.
For this reason, as shown in
As shown in
Electromagnetic shield film 242 is formed on the almost entire surface of lower sheet 213. This electromagnetic shield film 242 is formed by, for example, depositing a conductive material using a physical deposition method or a printing method. The physical deposition method may be performed by depositing metal such as copper and aluminum in vacuum. The printing method may be performed by forming a solid film on the entire surface or a mesh shape film using a paste containing a conductive material such as carbon or a silver paste.
Lower sheet 213 is provided with insulating protection film 243 for protecting electromagnetic shield film 242. In this case, an opening is provided in insulating protection film 243, so that insulating protection film 243 can be connected to the ground section by interposing the flexible wiring board therebetween.
In sheet type fluid circulating apparatus 210 having the above construction, the fluid is circulated in fluid path 215 provided in the inner space of flexible sheet 211 using fluid transport units 220 and 230. Accordingly, if a heater, heatsink fins, or an electronic cooler is connected to part of fluid path 215, the fluid can be heated, cooled, or maintained in a constant temperature. If an electronic device is connected to part of fluid path 215 where the heated or cooled fluid flows, the electronic device can be heated, cooled, or maintained in a constant temperature.
Flexible sheet 211 is constructed by bonding upper and lower sheets 212 and 213 formed of resin such as polyimide resin, polyester resin, or polyethylene terephthalate resin with each other using spacer 214, which may be formed of similar materials. Fluid path 215 is previously provided in spacer 214, and upper and lower sheets 212 and 213 are bonded to both surfaces of spacer 214, so that fluid path 215 having a closed structure can be formed.
In addition, the conductive films provided in a plurality of displacement generators 221 to 228 and 231 to 238 of fluid transport units 220 and 230, respectively, are formed, for example, by a deposition method or a sputtering method using an aluminum film or a copper film.
In order to facilitate deformation, only the areas of upper sheet 212 corresponding to displacement generators 221 to 228 and 231 to 238 of fluid transport units 220 and 230, respectively, may be formed in a smaller thickness than those of other areas. Alternatively, these areas may be formed of a material more susceptible to elastic deformation.
Water having high electric resistance is preferably used as the fluid. Alternatively, ethylene glycol can be used as the fluid. The ethylene glycol can be advantageously used even in a cold and snowy climate. In addition to water, any fluid that has low viscosity and high electric resistance can be adopted without limitation.
Hereinafter, a mechanism of fluid transport units 220 and 230 for circulating fluid using sheet type fluid circulating apparatus 210 according to the present embodiment will be described shortly.
In this embodiment, since two fluid transport units 220 and 230 are separately disposed, and flexible sheet 211 is used, fluid path 215 is locally expanded or contracted by the pressure of the fluid. For this reason, each fluid transport unit 220 and 230 can be individually operated. While fluid transport unit 220 will be described hereinafter, fluid transport unit 230 may have a similar construction. Also, the fluid is assumed to flow in a counter clockwise direction in fluid path 215 in
Firstly, displacement generator 221 of fluid transport unit 220 is deformed, so that fluid path 215 corresponding to displacement generator 221 is nearly closed. The deformation allows fluid path 215 to contract in a thickness direction, so that the fluid existing in this area is squeezed to both directions. In addition, this deformation is generated by applying different polarity voltages to the conductive films of upper and lower sheets 212 and 213 of displacement generator 221 using a control ciruit unit. For example, when a positive voltage is applied to the conductive film of lower sheet 213 of displacement generator 221, a negative voltage is applied to the conductive film of upper sheet 212 of displacement generator 221. For example, when the interval between the conductive films of upper and lower sheets 212 and 213 is set to 100 μm, a voltage of about 100 V is preferably applied.
Then, while fluid path 215 corresponding to displacement generator 221 is closed by deforming displacement generator 221, displacement generator 222 is similarly deformed. Similarly to displacement generator 221, this deformation is generated by applying different polarity voltages to the conductive films of upper and lower sheets 212 and 213 of displacement generator 222. As a result, fluid path 215 corresponding to displacement generator 222 is deformed similarly to fluid path 215 corresponding to displacement generator 221. When displacement generator 222 is deformed, fluid path 215 corresponding to displacement generator 221 is nearly closed in advance, so that the fluid is squeezed from displacement generator 221 to displacement generator 222.
Subsequently, while fluid path 215 corresponding to displacement generator 222 is nearly closed, displacement generator 223 is deformed, so that fluid path 215 corresponding to displacement generator 223 is nearly closed. Simultaneously, displacement generator 221 is restored to its initial state. At this moment, similarly to displacement generator 222, different polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generator 223. On the other hand, the same polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generator 221. Accordingly, a repelling electrostatic force is generated between the conductive films of upper and lower sheets 212 and 213 of displacement generator 221 to separate each other. As a result, fluid path 215 corresponding to displacement generator 221 is restored to its initial state, so that fluid path 215 is opened. This deformation allows the fluid existing in displacement generator 223 to be squeezed from displacement generator 222 to displacement generator 223.
Subsequently, while fluid path 215 corresponding to displacement generator 223 is nearly closed, displacement generator 224 is deformed, so that fluid path 215 corresponding to displacement generator 224 is nearly closed. Simultaneously, displacement generator 222 is restored to its initial state, and fluid path 215 corresponding to displacement generator 221 is closed. At this moment, similarly to displacement generator 223, different polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generator 224. On the other hand, the same polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generator 222. Accordingly, a repelling electrostatic force is generated between the conductive films of upper and lower sheets 212 and 213 of displacement generator 222 to separate each other. As a result, fluid path 215 corresponding to displacement generator 222 is restored to its initial state, so that fluid path 215 is opened.
This allows the fluid existing in displacement generator 224 to be squeezed in a direction from displacement generator 223 to displacement generator 224. On the other hand, the fluid flows into displacement generator 222, and portions of fluid path 215 corresponding to neighboring displacement generators 221, and 223 are closed.
Subsequently, while portions of fluid path 215 corresponding to displacement generators 221 and 224 are nearly closed, displacement generators 222 and 225 are deformed, so that fluid path 215 is nearly closed. Simultaneously, displacement generator 223 is restored to its initial state. At this moment, similarly to displacement generators 221 and 224, different polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generators 222 and 225. On the other hand, the same polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generator 223. Accordingly, a repelling electrostatic force is generated between the conductive films of upper and lower sheets 212 and 213 of displacement generator 223 to separate each other. As a result, fluid path 215 corresponding to displacement generator 223 is restored to its initial state, so that fluid path 215 is opened.
This allows the fluid existing in displacement generators 222 and 225 to be squeezed to displacement generators 223 and 226, respectively.
Then, while portions of fluid path 215 corresponding to displacement generators 222 and 225 are nearly closed, displacement generators 223 and 226 are deformed, so that fluid path 215 is nearly closed. Simultaneously, displacement generators 221 and 224 are restored to their initial states. At this moment, similarly to displacement generators 222 and 225, different polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generators 223 and 226. On the other hand, the same polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generators 221 and 224. Accordingly, a repelling electrostatic force is applied between the conductive films of upper and lower sheets 212 and 213 of displacement generators 221 and 224 to separate each other. As a result, portions of fluid path 215 corresponding to displacement generators 221 and 224 are restored to their initial states, so that fluid path 215 is opened.
This allows the fluid existing in displacement generators 223 and 226 to be squeezed to displacement generators 224 and 227, respectively.
Then, while portions of the fluid path 215 corresponding to displacement generators 223 and 226 are nearly closed, displacement generators 221, 224, and 227 are deformed, so that fluid path 215 is nearly closed. Simultaneously, displacement generators 222 and 225 are restored to their initial states. At this moment, similarly to displacement generators 223 and 226, different polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generators 221, 224, and 227. On the other hand, the same polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generators 222 and 225. Accordingly, a repelling electrostatic force is generated between the conductive films of upper and lower sheets 212 and 213 of displacement generators 222 and 225 to separate each other. As a result, portions of fluid path 215 corresponding to displacement generators 222 and 225 are restored to their initial state, so that fluid path 215 is opened.
This allows the fluid existing in displacement generators 221, 224, and 227 to be squeezed to displacement generators 222, 225, and 228, respectively.
Then, while portions of fluid path 215 corresponding to displacement generators 221, 224, and 227 are nearly closed, displacement generators 222, 225, and 228 are deformed, so that fluid path 215 is nearly closed. Simultaneously, displacement generators 223 and 226 are restored to their initial states. At this moment, similarly to displacement generators 221, 224, and 227, different polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generators 222, 225, and 228. On the other hand, the same polarity voltages are applied to the conductive films of upper and lower sheets 212 and 213 of displacement generators 223 and 226. Accordingly, a repelling electrostatic force is generated between the conductive films of upper and lower sheets 212 and 213 of displacement generators 223 and 226 to separate each other. As a result, portions of fluid path 215 corresponding to displacement generators 223 and 226 are restored to their initial states, so that fluid path 215 is opened.
This allows the fluid existing in displacement generators 222, 225, and 228 to be squeezed to displacement generators 223, 226, and 231, respectively.
By repeating the above operations, the fluid in fluid path 215 existing in fluid transport unit 220 can be successively circulated in the arrow direction of
In order to easily understand the circulation of the fluid using the displacement generators, operations of displacement generators 221 to 228 have been sequentially described in detail. In reality, according to a fifth embodiment of the present invention, a series of operations are performed by grouping a set of displacement generators 221, 224, and 227, a set of displacement generators 222, 225, and 228, and a set of displacement generators 223 and 226.
The electronic device cooler structure according to a sixth embodiment of the present invention includes the sheet type fluid circulating apparatus according to a fifth embodiment, a heater or a cooler provided in part of the fluid path, and a circuit board connected to the fluid path of the sheet type fluid circulating apparatus. This structure allows the electronic components mounted on the circuit board to be effectively cooled.
Firstly, as shown in
Wiring pattern 246 provided in both sides is connected to electromagnetic shield film 242 provided in lower sheet 213.
Flexible wiring board 255 is connected to the conductive films of displacement generators 231 to 238 of fluid transport unit 230. For example, the conductive films of upper and lower sheets 212 and 213 of displacement generator 231 are connected to wiring pattern 257 of flexible wiring board 255. In addition, wiring pattern 257 is provided in both surfaces of flexible wiring board 255, and connected to the conductive films of upper and lower sheets 212 and 213 of displacement generator 231. Similarly, displacement generators 232 to 238 are connected to wiring patterns 258 to 264 of flexible wiring board 255, respectively.
Wiring pattern 246 provided in both sides is connected to electromagnetic shield film 242 of lower sheet 213.
Wiring patterns 247 to 254 and 257 to 264 of flexible wiring boards 244 and 255 are connected to a control ciruit unit (not shown in the drawing). In addition, wiring pattern 246 of flexible wiring boards 244 and 255 is connected to the ground section (not shown in the drawing).
Sheet type fluid circulating apparatus 210 combined with flexible wiring boards 244 and 255 covers circuit board 266 on which electronic components 265 including semiconductor elements such as a CPU, passive elements, and low heat resistance elements are mounted to allow sheet type fluid circulating apparatus 210 to be connected to electronic components 265 that should be cooled as shown in
As described above, the electronic device cooler structure has been made.
It is possible to cool electronic component 265 by circulating the fluid cooled by heatsink fins 267 when fluid transport units 220 and 230 of sheet type fluid circulating apparatus 210 are driven while sheet type fluid circulating apparatus 210 is in contact with electronic component 265. In this case, since sheet type fluid circulating apparatus 210 has flexibility, it can be in contact with electronic component 265 even when electronic component 265 has various shapes. For this reason, flexible sheet 211 of sheet type fluid circulating apparatus 210 is deformed to have protrusions or hollows according to the shape of electronic component 265. However, fluid path 215 of sheet type fluid circulating apparatus 210 is also deformed according to the protrusions or hollows. Therefore, the fluid can flow without obstacles.
According to a sixth embodiment of the present invention, it is possible to obtain an electronic device cooler structure that can cool the electronic component by allowing the flexible sheet type fluid circulating apparatus to make contact with the electronic component.
The electromagnetic noises generated from the fluid transport unit are blocked by the electromagnetic shield film provided in the lower sheet so that the erroneous operation of the electronic component can be prevented. Furthermore, since the entire surface of the fluid path is covered by the electromagnetic shield film, the leakage of the fluid is prevented, so that the flexible sheet type fluid circulating apparatus can be safely used for a long time.
Although the electromagnetic shield film is provided in the lower sheet in this embodiment, it may be also provided in the upper sheet. This allows the electromagnetic noises from the fluid transport unit to be blocked for other electronic devices as well as the electronic components on the circuit board. In addition, this further prevents the leakage of the fluid.
Although a sixth embodiment has been described by exemplifying a circuit board as an electronic device to be cooled, the present invention is not limited thereto. For example, the present invention can be adopted when a specimen should be maintained in a constant temperature in other electronic or biomedical applications. In addition, when the electronic device should be maintained in a condition lower than a room temperature, an electronic cooler may be in contact with part of the fluid path of the sheet type fluid circulating apparatus instead of the heatsink fins to cool the fluid. Furthermore, when a heating is required to store the electronic device in a constant temperature, a heater may be in contact with part of the fluid path of the sheet type fluid circulating apparatus. In these cases, a temperature sensor may be provided in a device to be maintained in a constant temperature, and the temperature of the cooler or heater may be controlled based on the measurement result.
The sheet type fluid circulating apparatus according to a seventh embodiment includes a fluid path having a closed structure provided in the inner space of the stacked flexible sheet, fluid filled in the fluid path, a fluid transport unit provided in the fluid path of the flexible sheet to circulate the fluid in the fluid path, an electromagnetic shield film provided on both surfaces of the flexible sheet, and a ground section for grounding the electromagnetic shield film. In addition, the fluid transport unit is constructed of a heat pipe including a vapor path provided in the entire fluid path and a capillary path for circulating the fluid.
As shown in
In this case, upper sheet 274 has a 3-layer structure in which conductive film 272 is interposed between resin films 271 and 273. Similarly, lower sheet 278 has a 3-layer structure in which conductive film 276 is interposed between resin films 275 and 277. These conductive films 272 and 276 are commonly connected, although not shown in the drawing, and then connected to the ground G.
Similarly to a first embodiment, the sheet type fluid circulating apparatus having the above construction covers heat generating component 284 such as a semiconductor device such as a CPU. In this case, heat generating component 284 is mounted on circuit board 283 to constitute an electronic circuit in association with other electronic components although they are not shown in the drawing.
According to this embodiment, the heat generated in heat generating component 284 vaporizes the fluid of the heat pipe corresponding to the sheet type fluid circulating apparatus, and the vapor flows through a heatsink fin area expanded in a vertical direction to the drawing by vapor path 281. In the heatsink fin area, the vapor is cooled and re-converted into the fluid. The fluid flows through capillary path 280, and then, the contact area of heat generating component 284. By repeating these processes, it is possible to effectively cool heat generating component 284.
Conductive films 272 and 276 provided in upper and lower sheets 274 and 278 of sheet type fluid circulating apparatus effectively shield radiation of the electromagnetic noises to or from the electronic components including heat generating components 284 mounted on circuit board 283.
Reliability such as a life cycle of the heat pipe can be improved by providing conductive films 272 and 276 for preventing the fluid or the vaporized vapor from being leaked to upper and lower sheets 274 and 278.
As described in association with first to seventh embodiments of the present invention, it is possible to implement a compact and thin sheet type fluid circulating apparatus capable of effectively cooling other electronic components that have different shapes or generate a different amount of heat by connecting them to the fluid circulating apparatus, and an electronic device cooler structure using the same.
Hereinafter, another sheet type fluid circulating apparatus applied to a plasma display device according to eighth and ninth embodiments of the present invention will be described.
Conventionally, it has been known that a plasma display device (hereinafter, referred to as a PDP) generates a large amount of heat as its display brightness increases, this increases the temperature of the display panel, and irregular temperature distribution generates display quality degradation on its entire surface. When there is a large temperature difference on a display panel surface, a glass panel included in the display panel may be distorted and broken down finally.
Specifically, as shown in
For this reason, a conventional PDP has a plurality of cooler fans provided on the rear surface of the display panel using a spacer interposed therebetween and generates wind from the cooler fans to the display panel in order to reduce the temperature of the entire display panel. Although the conventional PDP having the cooler fans may entirely reduce the temperature of the display panel, it is difficult to reduce the temperature difference locally generated in the surface of the display panel.
Accordingly, a plasma display device for solving the above problem will be described in association with the following embodiments of the present invention.
That is, in this embodiment, the sheet type fluid circulating apparatus is used as a fluid circulating apparatus for cooling the plasma display device.
The PDP according to an eight embodiment of the present invention includes a display panel, and a fluid circulating apparatus that is provided on the rear surface of the display panel and has at least an upper cover and a bottom panel, in which the fluid for cooling the heat generated in the display panel is circulated, wherein a plurality of fluid path partitions for forming a fluid circulation path in the inner space of the fluid circulating apparatus are provided.
As shown in
The heat generated from display panel 301 is absorbed by the fluid circulated in circulation path 307 of fluid circulating apparatus 300, and externally radiated through heatsink path 313.
Generally, display panel 301 of the PDP is used in a vertically erected state, and the temperature distribution on the surface of display panel 301 is determined in this state. Therefore, directions of display panel 301 are defined as follows. In other words, in each drawing, a Y-direction denotes a vertical direction when display panel 301 is vertically erected, and an X-direction denotes a horizontal direction of display panel 301.
Hereinafter, an upper or upward direction of display panel 301 denotes a Y-direction, and a lower or downward direction denotes a reverse Y-direction.
Hereinafter, a construction of fluid circulating apparatus 300 will be described in detail with reference to
Fluid circulating apparatus 300 includes at least upper cover 304 and bottom panel 305, and a plurality of fluid path partitions 306 formed of metal such as aluminum having excellent thermal conductivity with a predetermined arrangement between upper cover 304 and bottom panel 305.
In this case, fluid path partition 306 and bottom panel 305 are preferably integrated in a single body. This allows a material for fluid path partitions 306 to be the same as that of the bottom panel. The cross-sectional shape of the fluid path partition 306 may be, for example, a rectangular or trapezoidal shape, and is not particularly limited if the width of fluid circulation path 307 can be arbitrarily formed.
As described with reference to
In addition, although it is shown that fluid path partitions 306 are divided in a vertical direction, and fluid circulation paths 307 are formed in a horizontal direction by interposing separating sections 308 therebetween, fluid path partitions 306 may entirely extend in a Y-direction on display panel 301 as shown in
Accordingly, in the high temperature portion E in display panel 301, the amount of heat absorption is increased due to a large flux of the fluid, so that the temperature increase is controlled. As a result, since the temperature increase in the high temperature portion E in display panel 301 is controlled, the temperature distribution on the surface of display panel 301 becomes uniform.
In addition, in order to be forcibly circulated the fluid in fluid circulating apparatus 300 from the upper side to the lower side, circulating pump 310 may be installed in internal or external heatsink path 313 of fluid circulating apparatus 300.
In order to effectively externally radiate the heat absorbed by the circulating fluid, heatsink cooler 311 having concave and convex shapes such as aluminum heatsink fins may be connected to at least a part of heatsink path 313 of fluid circulating apparatus 300, for example, with a thermal conductive sheet being interposed therebetween.
As a result, the fluid is forcibly circulated by circulation pump 310, and the heat of the fluid is effectively externally discharged through heatsink cooler 311, so that it is possible to more effectively reduce the temperature of display panel 301, and provide uniform temperature distribution.
Although it has been described that the flux of the fluid is controlled by changing the width w of fluid path partition 306 according to an eighth embodiment, the present invention is not limited thereto. For example, dimensions such as the depth h of the hollow formed between fluid path partitions 306, the width d of fluid circulation path 307, or the length L of fluid path partition 306 may be gradually changed based on the temperature distribution. In other words, the depth of the hollow and the width of fluid circulation path 307 may be increased and the length of fluid path partition 306 may be reduced in the high temperature portion of display panel 301.
Accordingly, the flux of the fluid flowing across fluid path partitions 306 can be optimally controlled based on the temperature distribution. Therefore, it is possible to reduce the temperature difference in display panel 301 as well as provide uniform temperature distribution.
Although it has bee described in an eighth embodiment that the fluid circulated across fluid path partitions 306 flows from the upper side to the lower side by circulation pump 310, the present invention is not limited thereto. For example, the fluid may flow from the lower side to the upper side by virtue of natural convection, or the fluid may flow in any arbitrary direction depending on the arrangement of fluid path partitions 306 and the location or rotating direction of circulation pump 310. When display panel 301 is disposed on a ceiling horizontally or with a slanted angle, the temperature distribution in display panel 301 is changed in comparison with that shown in
Although it has been described in an eighth embodiment that fluid circulating apparatus 300 is attached to the rear surface of display panel 301 with the thermal conductive paste being uniformly applied and interposed therebetween, the present invention is not limited thereto. For example, display panel 301 and fluid circulating apparatus 300 may be bonded with a thermal conductive sheet interposed therebetween. In this case, the thermal conductive sheet may include an aluminum thin film, a copper thin film, a carbon sheet, or a rubber sheet containing various thermal conductive materials.
Accordingly, the heat generated in display panel 301 can be more effectively transferred to fluid circulating apparatus 300.
In addition, a material of upper cover 304 or bottom panel 305 of fluid circulating apparatus 300 may include thermal conductive organic or inorganic materials such as aluminum, copper, aluminum nitride, carbon having excellent thermal conductivity, or a polymer sheet containing the above materials or a thermal conductive inorganic material having high thermal conductivity.
The fluid circulated in fluid circulating apparatus 300 may include a fluid material having low viscosity, high fire resistance, high ignition resistance, and a high boiling point, such as ethylene glycol, hydrocarbon based liquid.
Hereinafter, the result of measuring the temperature distribution in display panel 301 when fluid circulating apparatus 300 having the above construction is bonded with a high-resolution plasma display panel 301 having a wide area of 60 inches.
In this case, fluid circulating apparatus 300 has a plurality of fluid path partitions 306 of which the intervals and widths are gradually changed between the areas E and F, as shown in
Generally, the temperature distribution in display panel 301 has been measured when a white color is displayed on the entire surface of display panel 301 assuming that the temperature difference in display panel 301 becomes highest in this condition.
As a result, it was identified that the temperature distribution in display panel 301 can be made to be uniform when the temperature difference between the areas E and F of display panel 301 is not larger than 5° C.
As described above, according to an eight embodiment, it is possible to reduce the temperature of the entire display panel as well as provide uniform temperature distribution. As a result, it is possible to provide a highly-reliable plasma display device in which the display quality in the display panel is improved, and the difference of life cycles of the discharge cells caused by the temperature distribution is controlled. This effect is more remarkable in a wide-area high-resolution plasma display device.
Hereinafter, a second variation of a plasma display device according to an eighth embodiment of the present invention will be described with reference to
In
Referring to
Accordingly, since fluid path partitions 306 are not provided in the upper side of the area E corresponding to a high temperature portion in display panel 301 shown in
According to the above construction, since a fluid contact area is large in the high temperature portion, the absorbed heat amount can be large. On the contrary, since a fluid contact area is small in the low temperature portion, the absorbed heat amount is small. As a result, the temperature difference in the display panel can be reduced, and more uniform temperature distribution can be provided.
Although circulation path 307 was formed by dividing the fluid path in a vertical direction with fluid path partitions 306 and in a horizontal direction by interposing separating sections 308 across fluid path partitions 306, fluid path partitions 306 may be arranged to entirely extend in a Y-direction of display panel 301, but part of fluid path partitions 306 disposed in the high temperature portion may have a shorter length, as shown in
Although it has been described in an eighth embodiment that the lengths of the fluid path partitions or the arrangement of the fluid path partitions are changed between the high and low temperature portions, the present invention is not limited thereto. For example, the same effect can be obtained by arranging the fluid path partitions having predetermined unit length so as to have a lower concentration in the high temperature portion and have a high concentration in the low temperature portion.
Hereinafter, a plasma display device according to a ninth embodiment of the present invention will be described with reference to
Fluid circulating apparatus 330 shown in
The plasma display device according to a ninth embodiment of the present invention is characterized in that uniform temperature distribution can be obtained even when display panel 301 is disposed in any arbitrary direction such as a vertical, horizontal, or inclined manner.
As shown in
In fluid circulating apparatus 330, a plurality of fluid path partitions 326 having a constant width and a constant height (or a depth), for example, 500 μm are arranged with a constant interval in order to provide circulation path 307 for circulating the fluid in its inner space.
Fluid circulating apparatus 330 further includes flux controller 320 for controlling or adjusting the flux of the fluid, for example, across each of fluid path partitions 326 depending on the temperature distribution of display panel 301 in order to automatically reduce the temperature difference in display panel 301 and provide uniform temperature distribution. Flux controller 320 includes flux control electrodes 321 that are disposed between upper cover 324 and lower panel 325 of fluid circulating apparatus 330, for example, across fluid path partitions 326. Flux control electrodes 321 of each flux controller 320 are connected to a control ciruit unit (not shown in the drawing).
According to the above construction, the flux of the fluid can be controlled by adjusting an electrostatic force generated between each flux control electrode 321 by a voltage signal applied from the control ciruit unit to generate displacement in sheet-shaped upper cover 324 and change the interval between upper cover 324 and bottom panel 325 across fluid path partitions 326.
In addition, a plurality of temperature sensors (not shown in the drawing) such as a thermistor are provided in at least a part of fluid circulating apparatus 330, for example, a plurality of places on the surface of display panel 301, to detect the temperature of display panel 301.
It is possible to control or adjust the flux of the fluid flowing through circulation path 307 provided between fluid path partitions 326 by automatically changing, at least, an interval between upper cover 324 and bottom panel 325 across fluid path partitions 326 using an electrostatic force based on information from the temperature sensors.
In other words, the control of the control ciruit unit is performed such that the flux of the fluid is increased in the high temperature portion and reduced in the low temperature portion by changing the cross-sectional area of circulation path 307 using an electrostatic force based on the temperature information corresponding to the temperature distribution of display panel 301.
Accordingly, it is possible to automatically control the flux of the fluid in fluid circulating apparatus 330 in response to the temperature distribution of display panel 301 that can be varied depending on the environmental condition or method that display panel 301 is disposed, or a turn-on time of display panel 301. As a result, it is possible to automatically reduce the temperature difference of display panel 301 during operation to provide uniform temperature distribution.
According to a ninth embodiment of the present invention, it is possible to obtain a highly-reliable plasma display device capable of reducing the temperature of the display panel and providing uniform temperature distribution in the display panel.
Although a ninth embodiment of the present invention has been described by exemplifying a case that fluid path partitions having a constant width are provided with a constant interval, the present invention is not limited thereto. For example, the interval or the height of the fluid path partition, the depth of the hollow, the width or length of the fluid path partition may be differently provided or adjusted in advance in at least a part of the surface of the fluid circulation apparatus in order to provide uniform temperature distribution in the display panel.
Accordingly, it is possible to reduce the power consumption in the flux controller.
Although a ninth embodiment has been described by exemplifying a flux controller provided between the fluid path partitions, the present invention is not limited thereto. For example, the flux controller may be provided at least a part of the fluid path partitions. Specifically, the flux controller may be formed on the surface in a high temperature portion, and the intervals of the fluid path partitions may be reduced in other portions. Alternatively, the flux controller may be formed on the surface in a low temperature portion, and a constant flux may flow without the controlling in a high temperature portion.
Accordingly, since the flux controller provided in at least part of the fluid path partitions automatically controls the flux of the fluid, it is possible to obtain a plasma display device capable of providing uniform temperature distribution in the display panel with a simple construction.
Although a ninth embodiment has been described by exemplifying a flux controller which applies an electrostatic force between the flux control electrodes provided on the upper cover and the bottom panel to control the flux of the fluid, the present invention is not limited thereto. For example, a micro-electromagnetic valve may be provided across the fluid path partitions to control the flux of the fluid by switching the electromagnetic valve based on the temperature information. As a result, it is possible to automatically reduce the temperature difference in the display panel using a simple method.
Although a ninth embodiment has been described by exemplifying the polyimide resin film as a material of the upper cover of the fluid circulating apparatus to provide the flux control electrodes of the flux controller, the present invention is not limited thereto. For example, the upper cover of the fluid circulating apparatus may be formed of an electrically conductive metal thin-film such as an aluminum thin film laminated with resin, and an electrostatic force generated between the electrodes against the bottom panel using the metal thin film as a solid electrode may displace the laminated metal thin film.
Accordingly, it is possible to provide the flux control electrode in a simple construction, and use the flux control electrode disposed in one side as the upper cover as well. Therefore, it is possible to provide the fluid circulating apparatus with low cost.
Although a ninth embodiment has been described by exemplifying the flux control electrodes formed on inner surfaces of the upper cover and the bottom panel of the fluid circulation apparatus, the present invention is not limited thereto. For example, the flux control electrodes may provided in the outer surface of at least one of the upper cover and the bottom panel. Accordingly, it is possible to simplify an extracting electrode construction for connection with the control ciruit unit and eliminate necessity of forming an insulation film for coating the surface of the flux control electrode which is necessary to form in the inner surface. Therefore, it is possible to improve productivity of the fluid circulating apparatus.
Although it has been described in eighth and ninth embodiments that the fluid flows through the gap between the upper cover and the bottom panel as a fluid circulating apparatus, the present invention is not limited thereto. For example, as shown in
In other words, if heat pipe 340 is used, the temperature of display panel 301 is uniformly controlled by giving and receiving latent heat between hot and cold areas. Specifically, the fluid is vaporized in the high temperature portion, while the vapor is liquefied in the low temperature portion.
If self oscillating flow heat pipe 340 is used, the pressure difference is generated by volume expansion due to the phase change generated when the fluid is vaporized in the high temperature portion. This pressure difference circulates the fluid, so that the uniform temperature distribution can be provided in display panel 301.
Although it has been described in eighth and ninth embodiments that the fluid is circulated using a circulation pump, the present invention is not limited thereto. For example, a micro-pump shown in
Hereinafter, a construction of a micro-pump and a method of transporting fluid will be described with reference to
As shown in
As shown in
Although not shown in the drawing, the surfaces of first and second electrode sections 404 and 406 preferably have an insulation film. Accordingly, it is possible to prevent the short-circuit between the facing electrodes and transport other kinds of fluid than the insulating fluid.
As shown in
Also, the micro-pump having the above construction generates an electrostatic force between facing electrodes 405 and 407 by applying a predetermined voltage signal to coaxial electrodes 405 and 407 of the first and second electrode sections 404 and 406 facing each other. In this case, when the same polarity voltages are applied to the facing electrodes, a repelling force is generated. When different polarity voltages are applied, an electrostatic attracting force is generated. As a result, first member 401 formed of a flexible material is coaxially displaced by this electrostatic force.
Accordingly, the fluid input from inlet/outlet 409 is transported in a coaxial diameter direction and output from outlet/inlet 408 by coaxially gap 410 functioning as a fluid path formed between first and second members 401 and 402 with sealing member 403 being interposed using an electrostatic force. Similarly, the fluid input from outlet/intlet 408 can be output from inlet/outlet 409 of sealing member 403.
According to the above construction, since the fluid is coaxially transported, it is possible to obtain a micro-pump having a minute size but a large flux.
Since first and second electrode sections 404 and 406 are formed on the inner surfaces of first and second members 401 and 402, it is possible to obtain a large electrostatic force that is inversely proportional to the square of the electrode interval. Therefore, it is possible to reduce the applied voltage. This allows a control element having a low electric strength to be adopted, so that it is possible to implement a micro-pump with low cost.
The shape of electrode 405 or 407 is not limited to the coaxial form. For example, it may have a coaxial elliptical shape or a polygonal shape such as a rectangular.
Hereinafter, operations of the micro-pump will be described in detail with reference to
Although it has been described in
Although it has been described that first and second electrode sections 404 and 406 are formed on the outer surfaces of first and second members 401 and 402, the same effect can be obtained by forming them on the inner surfaces.
Firstly, as shown in
As shown in
As shown in
As shown in
While the micro-pump is operated, the voltages applied to each electrode are changed from a positive value to a negative value, but a predetermined voltage is being always applied.
The value of the voltages applied to the electrodes of each electrode section is optimally set by adjusting viscosity of the fluid, a shape of the electrode, a gap between the opposite electrodes, or the like. For example, in the above example, it has been described that the electrodes are formed on the outer surfaces of the first and second members, and receive a voltage of ±50 V. However, when the electrodes are formed on the inner surfaces, and the gap between the electrodes is set to ½ of an original, the micro-pump can be driven with a voltage of ±10 V to ±20 V.
According to the above operations, the micro-pump having a plurality of coaxial electrodes formed at least one of the first and second electrode sections sequentially opens/closes the gap in a coaxial diameter direction depending on the polarity of the voltage applied between the electrodes of the first and second electrode sections. When the gap is sequentially closed/opened, the fluid path is sequentially closed/opened, so that the fluid input from the inlet is coaxially transported to the outlet, and finally, output from the outlet.
Although it has been described that the coaxial electrodes of the second electrode section provided in the second member are set to the same voltage in the above micro-pump, the present invention is not limited thereto. For example, a plurality of coaxial electrodes or one electrode may be set the same voltage in the first electrode section, and the polarity of the voltage applied to a plurality of the coaxially neighboring electrodes of the second electrode section may be changed. As a result, as described above, the fluid can be transported by displacing the first member that is flexible.
Although it has been described that the first electrode section has two electrodes in the above micro-pump, the present invention is not limited thereto. For example, three or more electrodes can be provided, so that the fluid is stored in electrode portions of the opened gap by at least applying different polarity voltages to the coaxially neighboring electrodes, and the fluid can be intermittently transported with a predetermined time interval.
As describe above, it is possible to obtain a thin fluid circulating apparatus that can provide uniform temperature distribution in the display panel such as a plasma display panel by using a micro-pump that has a minute size and excellent transport efficiency and is able to transport a large flux of the fluid. In addition, since there is no driving noise generated from a circulation pump, it is possible to provide a silent thin plasma display panel.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-228193 | Aug 2005 | JP | national |
| 2005-254769 | Sep 2005 | JP | national |
| 2005-289775 | Oct 2005 | JP | national |
| 2005-290929 | Oct 2005 | JP | national |
