CN101227812A - cooling device - Google Patents

Abstract

The present invention provides a cooling device, which solves the problem of specific sundries and dust generated by light transmission in liquid crystal display equipment, and realizes cooling of liquid crystal panels and the like. Its structure is: for the heat generated by the liquid crystal panel and the polarizer due to the light source, through the first cooling module, the air in the liquid crystal display device that is isolated from the outside and circulated is used as cooling wind, and the liquid crystal panel or the polarizer as a heat generating body is cooled. For cooling, the second cooling module sprays the heating element and absorbs heat to cool the heating element.

Description

cooling device

technical field

The invention relates to the cooling of high-temperature bodies in electronic equipment, especially the cooling technology of liquid crystal panels and polarizers in electronic equipment such as liquid crystal display equipment that use light valve elements to enlarge and project information on the screen to display information such as images.

Background technique

A liquid crystal projector, which is a type of liquid crystal display device, has a liquid crystal panel as a light valve, modulates light from a light source, and projects and displays image information on the liquid crystal panel on a screen. Due to such a structure, in a liquid crystal projector, the light from the light source used to project image information is absorbed by light as it passes through the liquid crystal layer of the liquid crystal panel, and in the black mask (Blackmask) or the like that shields unnecessary light sources It is also absorbed by light, and the temperature of the liquid crystal panel rises due to such light absorption. In addition, light from the light source that does not have a predetermined polarization axis is absorbed by polarizing plates disposed before and after the liquid crystal panel. The heat accumulated in the polarizing plate is transferred to the liquid crystal panel, causing the temperature of the liquid crystal panel to rise.

Excessive temperature rise of the liquid crystal panel lowers the reliability of the liquid crystal panel, so in the same way as in other electronic equipment, in the liquid crystal projector, the air cooling method that uses the fan installed in the equipment to obtain external air and blow air , to cool the liquid crystal panel and polarizer.

In recent years, due to the diversification of usage conditions of liquid crystal display devices, higher luminance of display screens has been demanded, and the light irradiated on the liquid crystal panels of the liquid crystal display devices has become stronger. On the other hand, the demand for cheaper products on the market is also stronger, and the LCD panels used are becoming smaller and smaller. When these factors are combined, the heating density of the liquid crystal panel becomes very high. Such an increase in the temperature of the liquid crystal panel accelerates the deterioration of the quality of the liquid crystal panel, which becomes a problem in the product life of the liquid crystal display device, and the cooling device is also required to increase the cooling capacity corresponding to the temperature increase.

In addition, if a display device such as a liquid crystal display device is irradiated with light and the projection is enlarged, if debris and dust remain in the device, they will be displayed due to the projected light, resulting in deterioration of the picture quality, so it is desirable to cool the heat generating body The method is a cooling method that does not communicate with outside air.

Various studies have been made on a liquid cooling method in which a liquid cooling medium is provided as described in Patent Document 1 as a method of improving cooling capacity in response to foreign matter and dust. In such a cooling device, a heat-receiving member sealed with a liquid cooling medium is arranged in close contact between the liquid crystal panel and the polarizing plate, so that the heat accumulated on the liquid crystal panel and the polarizing plate is transferred to the heat-receiving member flowing through the liquid cooling medium, and the heat is transferred through the liquid pump. The heated liquid cooling medium is transferred to a radiator disposed at a distant position, and the heat is radiated by the radiator. This liquid cooling medium is circulated between the heat receiving member and the radiator by a liquid pump, and the cooling capacity is improved by setting an optimal heat exchange state for heat transfer.

In addition, in the cooling device described in Patent Document 2, the heat receiving member having the flow path through which the cooling medium flows is arranged so as to be in close contact only with the peripheral area except the light transmission area of the liquid crystal panel module irradiated by the light source. The heat accumulated in the liquid crystal panel is transferred to the cooling medium circulating around the liquid crystal panel, and the heated cooling medium is transferred to the heat dissipation unit arranged at a distant position through the pump, and the heat dissipation unit dissipates heat, and the cooling medium does not directly Accepting the irradiation of light avoids the impact on the quality of the projected picture.

Furthermore, there is a cooling device described in Patent Document 3 as a method for cooling a high-temperature body such as a liquid crystal panel while blocking foreign matter and dust mixed into a liquid crystal display device. The cooling device makes the liquid crystal display device in an airtight state through the frame, temporarily compresses the air in the frame, and sprays it toward the high-temperature body through the nozzle. The high temperature body is cooled by the air flow from the nozzle whose temperature is lowered due to the adiabatic expansion. At this time, the temperature rise caused by the compression is dissipated to the outside air by the cooling fins provided outside the compression device and in contact with the outside.

Here, the cooling module described in Patent Document 4 is not an example of a cooling device related to a liquid crystal display device, but is a cooling device that performs cooling using two different cooling modules in combination. This cooling device is provided with a cooling circulation system that receives heat from a heating element through a cooling medium and transfers the heat, and a cooling circulation system that circulates a cooling medium that is compressed by a compressor and adiabatically expanded to lower its temperature. A cooling system that receives heat from a heating element and transfers it, is thermally connected to another cooling system of the latter and absorbs the heat of the cooling medium, and dissipates heat in the latter's circulation system.

In the patent documents listed above, there are the following problems that must be solved.

In the cooling device described in Patent Document 1, since the light irradiated from the light source passes through the liquid cooling medium, if air bubbles or dust are mixed in the liquid cooling medium, a new problem arises that an image of the air bubbles or dust is projected on the image. In addition, if a temperature difference occurs in the liquid cooling medium, the problem of image shake occurs due to convection in the liquid cooling medium, etc., and the liquid cooling medium is deteriorated due to light irradiated from the light source, causing quality deterioration, causing light to affect the liquid crystal. The transmittance of the panel is lowered, and the illuminance of the image is lowered.

In the cooling device described in Patent Document 2, in the area avoiding the area through which the light irradiated from the light source passes through, the cooling cooling medium such as the liquid crystal panel is circulated to perform cooling, so it is possible to avoid the cooling due to the influence of light. The problem of Patent Document 1 arises in the cooling medium, but the cooling medium must efficiently transfer the heat of the liquid crystal panel and the polarizing plate generated by the light irradiated from the light source to the surroundings. Therefore, in terms of heat transfer, high light transmittance and high thermal conductivity materials with good light transmittance and high coefficient of thermal conductivity should be used. But the reality is that such high light transmission and high thermal conductivity materials are limited materials, and the price is high, which has become a problem in terms of commercial product cost. In addition, since the air inhaled by the heat dissipation unit brings in sundries and dust, some liquid crystal display devices require dust-proof glass and the like to be provided on the surface of the high thermal conductivity material and the liquid crystal panel.

In the cooling device described in Patent Document 3, the pressure and temperature of the injected air can be controlled by controlling the compression state of the compressor, but a large-scale device such as a compressor is required. Furthermore, the rapid cooling of the air caused by the adiabatic expansion liquefies the moisture in the air inside the device, and if these water droplets adhere to the liquid crystal panel, etc., it will cause image degradation. In addition, the air flow injection cycle of the compressor and the like cause periodic fluctuations in temperature, and this cycle may also affect the image.

In order to attach and detach the cooling device to the electronic device, the cooling device described in Patent Document 4 is provided independently of the electronic device and the cooling device, thereby improving the operability of attachment and detachment. However, in order to make any one of the electronic equipment that requires airtightness that cannot be attached and detached from the cooling device to be cooled by a cooling method, two independent cooling circulation systems must be installed, so that the cooling circulation system Mutual thermal connection can only be a combination of indirect heat transfer, and there is redundancy in the cooling device.

[Patent Document 1] Japanese Patent Laid-Open No. 1-159684

[Patent Document 2] Japanese Patent Laid-Open No. 2005-275189

[Patent Document 3] Japanese Patent Laid-Open No. 2005-148624

[Patent Document 4] Japanese Patent Laid-Open No. 2004-319628

Contents of the invention

The cooling device of the present invention is configured to include: a first cooling module that cools the high-temperature body of the electronic device through a circulating first cooling medium; a second cooling module that cools the first cooling medium through a circulating second cooling medium; and a drive A cooling medium drive module for circulating the first cooling medium and the second cooling medium.

In addition, the cooling device of the present invention is configured to include: a cooling medium drive unit including a first pump chamber for sucking in and discharging air and a second pump chamber for sucking in and discharging cooling liquid, and the first pump chamber and the second pump chamber operate in conjunction with each other. The air cooling module includes: a nozzle for ejecting cooling air to a liquid crystal panel or a polarizer, and the above-mentioned cooling air that flows into and is sucked and discharged through the above-mentioned first pump chamber and cools the above-mentioned cooling air, and at the same time flows out the cooled cooling air to the above-mentioned nozzle The heat exchange part, the air cooling module is arranged inside the airtight part of the electronic equipment with built-in liquid crystal panel and polarizing plate; The heat receiving part of the exchange part; the heat dissipation part is arranged outside the above-mentioned airtight part to dissipate heat from the coolant absorbed by the above-mentioned heat-receiving part; The cooling fluid pipeline is connected and circulated in the cooling part.

According to the cooling device of the present invention, it is possible to provide an electronic device such as a liquid crystal display device having high reliability and high screen quality without temperature degradation of internal components.

Description of drawings

FIG. 1 is a schematic configuration diagram of a liquid crystal display device using a cooling device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of cooling temperature states of the cooling device according to the embodiment of the present invention.

Fig. 3 is a schematic diagram showing the relationship between the flow rate of the cooling medium and the amount of heat absorbed by the cooling medium.

Fig. 4 is a schematic diagram illustrating a cooling heat exchange state of an embodiment of the present invention.

Fig. 5 is a schematic diagram showing physical property values of air and water.

Detailed ways

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a model of a liquid crystal display device using a cooling device according to an embodiment of the present invention. The component to be cooled of the liquid crystal display device is a liquid crystal panel irradiated by light, etc., and the cooling device in the embodiment of the present invention preferably solves the unique cooling problem of the light-transmitting liquid crystal panel. In addition, not limited to liquid crystal display devices, it is also effective in other electronic devices that require isolation from the outside air.

The liquid crystal display device 1 modulates light irradiated from a light source to form image information, and projects the formed image information on a screen for enlarged display. The liquid crystal display device 1 has an optical unit 3 inside a housing 2, and a projection lens 4 projects image information formed by the optical unit 3 onto a screen (not shown). An embodiment of the present invention includes a cooling device 5 for cooling the optical unit 3 .

First, an outline of the function and configuration of the optical unit 3 that forms image information will be described with reference to FIG. 1 . The optical unit 3 is a structure for performing optical processing on the light emitted from the light source and forming image information in an optical image. constitute.

The illumination optical system 31 is configured such that the light irradiated by the light source 311 is reflected by the reflector 312 and emitted as parallel light, and the light separated into a plurality of parts by the lens array 313 composed of small lens groups is formed by the superimposed lens 314 in the following description. image on the LCD panel.

The color separation optical system 32 has the following functions: dichroic mirrors 321 (blue separation) and 322 (green and red separation) that transmit and reflect the light emitted from the illumination optical system 31, and reflection of the reflected light. The mirrors 323, 324, and 325 separate the light into red, green, and blue colored lights.

The red, green, and blue light separated by the color separation optical system 32 is projected onto a liquid crystal panel for each color light of each optical conversion element 33 , which will be described later.

The incident-side polarizer 331R (G, B) and the output-side polarizer 333R (G, B) are arranged at positions sandwiching the liquid crystal panel 332R (G, B), and these three sets constitute the optical conversion element 33 . The color lights whose polarization directions are aligned in substantially the same direction enter the respective incident polarizers 331 (R, G, B), but only the polarized light in the substantially same direction as the polarization axis of the light passes, and the other lights are absorbed. Of the light emitted from the liquid crystal panel 332 (R, G, B), only light having a polarization axis parallel to the transmission axis of the light passing through the incident-side polarizing plate 331 (R, G, B) is transmitted through each outgoing-side polarized light. Plate 333 (R, G, B), other light is absorbed. Therefore, the temperature of the incident-side polarizer 331 (R, G, B) and the output-side polarizer 333 (R, G, B) rises due to the absorbed light. In particular, the polarizing plate on the emission side has a large amount of heat storage.

Four right-angle prisms for synthesizing the image information of each color light modulated by each liquid crystal panel 332 (R, G, B) and emitted from each output side polarizer 333 (R, G, B) to form a color image, Combining color synthesis optical system 34.

The projection lens 4 is composed of a plurality of lenses, and enlarges and projects the color image formed by the color synthesis optical system 34 onto the screen.

In the above-mentioned liquid crystal display device 1, for example, there are polarizing plates 331 (R, G, B), 333 (R, G, B) for temperature rise caused by light from the light source and a liquid crystal panel 332 (R, G, B). ) cooling device 5 for cooling.

The basic configuration of the cooling device 5 of the liquid crystal display device 1 will be described with reference to FIG. 1 .

First of all, in the embodiments of the present invention, the features that are greatly different from the existing cooling devices for electronic equipment are the use of pumps that drive two types of cooling media, and the cooling of the two types of cooling media driven by the pump. . The pump 51 is a vortex pump, and the pump chamber of one vortex pump 51 is divided into a first pump chamber 511 and a second pump chamber 512 to form two independent pump flow paths. The first pump chamber 511 and the second pump chamber 512 are respectively provided with a first inflow port 513 and a second inflow port 514 for the cooling medium, and a first outflow port 515 and a second outflow port 516 for the cooling medium.

The cooling medium of the two cooling modules is driven by the respective pump chamber. The cooling system in which the cooling medium is circulated by the first pump chamber 511 of the vortex pump 51 is a first cooling module composed of a plurality of pipes 551 circulatively connecting the heat receiving member 52 , the heat radiating member 53 and the liquid tank 54 . In addition, the cooling system that transfers the cooling medium from the second pump chamber 512 of the vortex pump 51 is a second cooling module, which is composed of an air heat exchange member 56 connected through a pipe 552 and an injection module having a nozzle group 57, wherein the nozzle group 57 includes A control part that sprays the transferred cooling medium.

The cooled body of the liquid crystal display device 1 of the embodiment of the present invention is three groups of liquid crystal panels 332 (R, G, B) and polarizers 331 (R, G, B), 333 (R, G, B) of light transmission part. The cooling device 5 for cooling the liquid crystal panel and the like adopts a cooling method of spraying low-temperature wind directly on the plane of the liquid crystal panel and polarizing plate, which eliminates the problem of cooling the light-transmitting parts of the liquid crystal panel and the like in the liquid cooling method.

As shown in Figure 1, as the cooled body, the liquid crystal panel 332 (R, G, B) and the polarizing plate 331 (R, G, B), 333 (R, G, B) with three colors of light, so the present invention The cooling device 5 of the embodiment has at least three sets of nozzles 57 . When cooling other heat-generating electronic components in the liquid crystal display device 1 , if necessary, the nozzle 57 is arranged to face the object to be cooled, and cooling can be performed in the same manner.

Here, the configuration and operation of the first cooling module and the second cooling module will be described. First, the configuration of the second cooling module for cooling the liquid crystal panel 332 , the polarizing plates 331 , 333 , etc., which are directly cooled, and the method of injecting air will be described with reference to FIG. 1 .

The sprayed air cooling medium is operated by the second pump chamber 512 of the vortex pump 51 . That is, from the second inflow port 514 provided in the second pump chamber 512, the air inside the liquid crystal display device 1 sealed off from outside ventilation flows in, and the air is transferred to the liquid crystal display device 1 through the second outflow port 516 of the vortex pump 51. The two pipes 552 are connected to the air heat exchange unit 56 . Inside the air heat exchange member 56 , flow paths (not shown) having a fin shape are formed in order to secure a large contact area with the air and to achieve heat exchange when the transferred air circulates. The transferred air stays in the air heat exchange member 56 and is sprayed toward the object to be cooled by the nozzle 57 .

Here, the formation of the low-temperature (T2) jet wind when cooling the high-temperature bodies 332, 331, and 333 (temperature: Th) will be described with reference to FIGS. 1 and 2 . Fig. 2 is a schematic diagram showing a heat conversion state of the cooling device according to the embodiment of the present invention.

The air sucked in the air heat exchange part 56 is the air in the airtight liquid crystal display device 1, and it is preferable in terms of isolating foreign matter and dust from the outside. After (temperature: Tc) the air. The heat (temperature: Tc) of the air after this heat absorption is diffused by the housing 2 etc. when floating inside the liquid crystal display device 1 and dissipated, resulting in a slightly lower temperature (T1), but the liquid crystal display device 1 also retains other heat. If the absorbed air heat is not completely released, the air will still be in a temperature state close to the temperature (Tc) after absorbing heat. Even if the air (temperature: Tc) in this heat-absorbing state is injected to the object to be cooled 331, 332, 333 (temperature Th), since the high temperature state of the object to be cooled cannot be sufficiently cooled, the injected air must be at a low temperature. (Temperature: T2) jet wind.

The formation of injected low temperature (T2) air is illustrated. The air heat exchange member 56 is thermally connected to the heat receiving member 52 of the first cooling module described later. The air in the housing 2 is sucked into the air heat exchange member 56, and the heat (temperature: T1) of the circulating air is heated by the liquid cooling medium circulating in the heat receiving member 52, thereby forming low temperature (T2) air. The cooled low-temperature (T2) air staying in the air heat exchange member 56 is sprayed from the nozzle 57 to the high-temperature bodies 332, 331, 333 (temperature: Th) continuously or intermittently with a predetermined cycle by the injection control mechanism, thereby The liquid crystal panel 332, the polarizing plates 331, 333, and the like are cooled (temperature: Tc). The following cycle is repeated: the air after absorbing heat from the high temperature bodies 332, 331, 333 (temperature: Tc) floats in the liquid crystal display device 1 again, dissipates heat through the frame body 2 of the liquid crystal display device 1 (temperature: T1), and at the same time The cooling medium liquid sucked by the second inflow port 514 of the vortex pump 51 and circulated in the heat receiving member 52 of the first cooling module is heated to become low-temperature (T2) wind and sprayed by the nozzle 57 .

Here, first, the heat conversion from the portion close to the object to be cooled will be sequentially described. The cooling of the liquid crystal panel 332 and the polarizing plates 331 and 332 is performed by heat exchange between the interface between the air and the object to be cooled and the heat transfer of the air cooling medium. To illustrate these heat exchanges, the characteristics of the physical properties of air involved in the heat exchange of the present invention are shown in FIG. 5 in comparison with water as a general liquid cooling medium.

First, the amount of heat Ws received by the air cooling medium at the interface between the object to be cooled and the air is expressed by the following formula:

Ws=(heat transfer rate)×(temperature difference)×(contact area) ……(1)

Here, the heat transfer coefficient is a function related to Prandtl's constant and thermal conductivity, and varies according to the flow rate of the cooling medium. Generally, the ratio of the liquid cooling medium to the air cooling medium is about 20 times. That is, in order to obtain the cooling effect of the air cooling medium at the same temperature as that of the liquid cooling medium, the contact area of the liquid crystal panel, the polarizer, and the like with the air must be enlarged by at least about 20 times.

The liquid crystal panel and the polarizing plate are arranged in an optimal state optically, and it is difficult to arrange the entire surface of each in contact with the heat-receiving member through which the liquid cooling medium flows. Therefore, the heat-receiving member must be arranged between the liquid crystal panel 332 and the output-side polarizing plate 333 . Therefore, in cooling methods using a liquid cooling medium, heat transfer takes place only over a limited contact area.

In contrast, in the cooling method of spraying air cooling medium, liquid crystal panel 332 and polarizers 331, 333 are arranged to provide gaps through which air can flow, so that air cooling medium is sprayed on two planes. This means that it is easy to increase the contact area with the cooling medium, for example, it can be enlarged about 6 times. Furthermore, a heat sink member having a contact area about 3 to 4 times larger is provided on the mounting member of the liquid crystal panel 332 and the polarizing plates 331 and 333 .

From the above, it is easy to expand the contact area with the air cooling medium to about 20 times the contact area with the water-cooled heat receiving member, and the air cooling medium can also ensure the same transfer heat as the heat transfer to the liquid cooling medium.

Next, the heat absorption amount Wt of heat transfer will be described. The heat absorption Wt of the heat transfer of the air cooling medium is expressed in the following formula

Wt＝(density)×(specific heat)×(flow rate)×(temperature difference) ……(2)

Here, as shown in Figure 5, the density of the liquid cooling medium and the air cooling medium is 1:0.00129, and the specific heat is 1:0.24. When the temperature difference is the same, the heat transfer performance of the air cooling medium is about 1/3200 of the heat absorption Wt of the liquid cooling medium.

Therefore, in order to obtain the necessary heat (Wt) while spraying low-temperature (T2) air and cooling it to the working cooling temperature (Tc), it is necessary to greatly increase the flow rate of sprayed air.

Here, since the larger the temperature difference (ΔT), the larger the heat absorbed, the more the air jetted through the nozzle 57, compared with the air in the state of temperature (T1) after being dissipated by the thermal diffusion of the frame 2, etc. Cooled by the liquid cooling medium of the first cooling module and sprayed with low-temperature (T2) air, as described above, the amount of heat absorbed from the high-temperature body is increased. Next, the first cooling module for making the air to be sprayed in the air exchange unit 56 at a low temperature (T2) will be described.

Using the first piping group 551, the first pump chamber 511 of the vortex pump 51, the heat receiving member 52, the heat dissipation member 53, and the liquid tank 54 form a closed circulation flow path to form a first cooling module, which transfers liquid in the closed circulation flow path. A device that cools the medium and exchanges heat through two heat exchangers (heat receiving part 52 and heat radiating part 53). As described above, the heat receiving member 52 has a flow path through which the liquid cooling medium flows, and is thermally connected to the air heat exchanging member 56 .

The air transferred in the air heat exchange member 56 dissipates heat while staying in the liquid crystal display device 1 , but the incompletely dissipated heat heats the liquid cooling medium circulating in the heat receiving member 52 to become low-temperature air ( T2 ). On the other hand, the heated liquid cooling medium (temperature: T2 ) is transferred through the pipe 551 connected to the first pump chamber 511 of the vortex pump 51 , and transferred to the heat dissipation member 53 .

Here, the heat dissipation member 53 is installed outside the frame body 2 of the liquid crystal display device 1, and the heat (T2) of the heated liquid cooling medium passes through a fan (not shown) installed outside the frame body, etc. It is cooled by ventilating with the outside air (temperature: Ta), and dissipates heat outside the housing 2 . The coolant liquid (temperature: Ta) after heat radiation flows through the pipe 551 and circulates to the heat receiving member 52 .

That is, the respective cooling media are circulated and driven in the cooling modules of the two systems by the vortex pump 51 as one cooling medium driving part. In addition, by combining the advantages of both of the cooling modules, the cooling device 5 for cooling the object to be cooled unique to the liquid crystal display device 1 is realized.

Next, the state of cooling in the embodiment of the present invention will be described with reference to FIG. 3 and FIG. 4 . Fig. 3 is a schematic diagram showing the relationship between the flow rate of the cooling medium and the heat absorption amount of the cooling medium in a model. The characteristic curve shown in FIG. 3 is merely a qualitative representation, and the relationship between the flow rate (Q) of the cooling medium and the heat absorption amount (W) is a proportional relationship as shown in the above-mentioned (2 formula).

In addition, as the pump 54 for driving the cooling medium in the embodiment of the present invention, since it is divided into two parts, the first pump chamber 511 and the second pump chamber 512, when the pumps have the same shape, compared to the original pump chamber which is not divided, The flow rate (Q1) of the vortex pump in the flow path, the flow rate of the cooling medium liquid driven in each pump chamber is approximately halved to (1/2·Q1)

Therefore, in the case where the amount of cooling medium (1/2·Q1) circulating in only one pump chamber absorbs heat from the object to be cooled (liquid crystal panel or air) and cools it, the amount of heat that can be absorbed becomes W1= 1/2W1 (point b). The heat absorption W1 (point a) necessary for cooling the temperature of the object to be cooled (Th) to the predetermined operating cooling temperature (Tc) cannot be obtained. In order to make the object to be cooled (Th) reach the working cooling temperature (Tc), the difference ((W1)-(W1')) between the absorption of the cooling medium driven by another pump chamber and the heat absorption (W1') is obtained to obtain the desired cooling performance.

That is, the cooling device in the embodiment of the present invention avoids inappropriate liquid cooling medium when cooling the light-transmitting liquid crystal panel, etc., and uses air cooling medium for cooling, and the liquid cooling medium driven by the first pump chamber 511 The heat absorption ("b") of the second pump chamber 512 and the heat absorption ("c") of the air cooling medium driven by the second pump chamber 512 realize the cooling of the temperature (Th) of the heating element such as the liquid crystal panel (temperature: Tc) method.

However, if the heat absorption of the air cooling medium is at the same flow rate as that of the liquid cooling medium, as described above, the heat absorption is only about 1/3200. In the embodiment in which one drive pump 51 is divided into two pump chambers, the liquid cooling The driving flow rate of the medium and the air cooling medium must be the same, so as shown in Figure 2, it stays at increasing the heat absorption ("c"), and the desired heat absorption W1 cannot be obtained. Therefore, it is necessary to store and circulate about 3200 times as much air cooling medium.

The heat exchange state of the cooling system according to the embodiment of the present invention will be described with reference to FIG. 4 .

FIG. 4 is a schematic diagram illustrating a cooling heat exchange state of a cooling method according to an embodiment of the present invention based on consideration of a general cooling method. Figure 4(a) models the basic general cooling conditions. Fig. 4(b) illustrates the cooling condition of the embodiment of the present invention in a model. The horizontal direction (axis) represents the time concept of the flow rate related to the heat exchange, and the vertical direction (axis) represents the temperature concept related to the heat exchange.

As shown in Figure 4(a), in general, the cooling device of the heat generating body of electronic equipment is used to cool the heat generation temperature (Th) of the cooled body to the cooling working temperature (Tc) below the allowable temperature (T0) of the cooled body , through the cooling medium of temperature (Ta) for heat exchange, the heating temperature (Th) of the object to be cooled is heated by the liquid cooling medium of the heating part of the water-cooling method or the circulating air of the air-cooling method, and the heat required for the cooling temperature (Tc) is obtained (Temperature change: (Th-Tc)), that is, the heat (W1) absorbed by the cooling medium is the amount of heat ( Temperature: (Ta-Tc)), which is equal to the heat released by the cooling medium (W2). Thus, in such a cooling device, heat transfer due to heat absorption and heat dissipation is balanced.

In the cooling device of the embodiment of the present invention, according to the relationship between the heat absorption (W1) and the heat dissipation (W2), use Fig. 4 (b) to illustrate the cooling state in order to obtain the prescribed heat (W1), including the above-mentioned The content is explained again.

The temperature (Tc) of the air in the liquid crystal display device 1 after being sprayed onto the heat generating body and absorbing heat is assumed to be the temperature (T1) of the air that is thermally diffused and dissipated by the frame 2 and the like while staying in the frame 2 . Air at the temperature (T1) is sucked through the second inlet port 514 of the second cooling module, enters the pump chamber 512, passes through the second outlet port 516, flows through the piping 552, and is transferred to the air heat exchange member 56.

Assuming that the air at the temperature (T1) is sprayed from the nozzle 57 to the object to be cooled (temperature: Th), and the air (temperature: T1) sucked into the pump chamber 512 absorbs heat from the temperature (Th) of the object to be cooled, the frame 2 The amount of natural heat dissipation is large, which is preferable from the viewpoint of air cooling performance in which the air temperature is lowered. However, in reality, it is difficult to significantly lower the air temperature ( T1 ) only by this natural heat dissipation, so it is difficult to cool to a predetermined cooling temperature (Tc).

Here, by lowering (temperature: T2) the temperature (T1) of the injected air, thereby increasing the heat absorption from the temperature (Th) of the object to be cooled, circulating in the air heat exchange part 56 of the second cooling module, to The first cooling module cools the stored air (temperature: T1) (temperature: T2). The thermal switching state of the first cooling module is the same as above.

Here, an example will be described assuming that the cooling medium driven by the pump chamber 512 is air in a state where the volumes of the two divided pump chambers of the vortex pump 51 are equal. Using the pump with the pump chamber divided into two, the number of pumps is small, and the effect of assembly and installation is easy to achieve. On the contrary, the amount of cooling medium is halved without reducing the cooling capacity, which will be described later.

The amount of heat transfer between the air cooling medium and the liquid cooling medium is about 1:3200 different, so in cooling devices with the same configuration, the cooling performed by the air cooling medium is compared to the cooling performed by the liquid cooling medium, as long as the amount is not increased by this ratio If the flow rate of the air is lower, the cooling with the same performance as that of the liquid cooling medium cannot be performed when heated. In other words, if the injection method of the air sprayed by the nozzle 57 is continuous, then in an embodiment of the present invention in which each cooling medium is driven by one vortex pump 51, the flow rate of the sucked air is the same as the flow rate of the liquid cooling medium, and cannot be performed. Defined cooling of hot bodies. In order to make up for the shortage of this amount of heat transfer, it is performed by controlling the injection method of air.

The injection of air from the nozzle 57 for cooling the high-temperature body drives the vortex pump 51 and sends a predetermined amount of air into the air heat exchanger 56, and is controlled and injected by the injection control module at a predetermined cycle. Since the nozzle 57 is opened at a predetermined period, it is assumed that the air is stored in a constant compressed state in the air heat exchange member 56 during the injection period, rather than adiabatically compressed. In addition, since the nozzle 57 is injected through the injection device not shown in the figure, it is opened by the nozzle due to the pressure resistance of the nozzle, so it is expected that the temperature of the injected air due to the constant adiabatic expansion of the air will drop, but the temperature caused by the adiabatic expansion The descent is not intentional, but determined by proper compression and expansion. The purpose of spraying is to ensure an instantaneous air flow rate in order to transfer heat between the air and the object to be cooled.

Here, as long as the flow rate of the pump is constant, the flow rate of the circulating air is a continuous air flow, or periodic intermittent injection, and the flow rate of the air cooling medium is constant within a specified time, so the total heat absorption is constant, but due to Since the amount of heat absorbed is proportional to the flow velocity, it is more effective to increase the jet flow velocity than to increase the flow velocity of the air cooling medium flowing.

However, in a pump that does not change the driving flow rate of the cooling medium, the total amount of air driven does not change, so the total amount of air is accumulated for a predetermined time in order to absorb a predetermined amount of heat. This predetermined time accumulation cycle is performed, that is, the driving is performed periodically.

Since the heat absorption of the heat generating body progresses by periodically spraying the cooling air, the heat generation temperature of the object to be cooled rises after the cooling state at the time of spraying. If the temperature rise of the object to be cooled lasts for a long time, it may affect the liquid crystal panel. However, during the temperature rise of the liquid crystal panel, low-temperature wind is sprayed intermittently to cool it, so that the allowable temperature of the heat generating body can be ensured on average (T0 ).

On the other hand, cooling is carried out by spraying air periodically, and the cooling temperature of the object to be cooled fluctuates according to the period of spraying. In order to deal with this problem, the injection period of the cooling air to the object to be cooled is preferably the field frequency for forming image information, or an integral submultiple of the field frequency.

In liquid crystal display devices, etc., the pixels constituting an image are sequentially scanned, and one image is formed by the field frequency. If the cooling air is injected synchronously with the field frequency, the pixel position on the scanned screen is always a certain scanning position at the injection timing of the cooling air, so the scanning time of the same place on the screen is cooled, and the temperature on the screen The state of the brightness change of the image caused by the change has the same period, so the visual change can be made constant.

Since the field frequency is, for example, 1/60 second in the NTSC TV system, it is ejected after accumulating 60 times the above-mentioned 1/3200. That is, about 1/50 of the amount of absorbed heat needs to be sufficient when spraying the air cooling medium. The diameter of the nozzle is formed so that the flow velocity of the nozzle is 50 times that of the conventional liquid cooling medium.

Embodiments of the present invention use the following control method: do not increase the flow rate of the total vortex pump 51 by the air flow injected by the nozzle 57, and suppress the enlargement of the cooling device. For the purpose of dust prevention of electronic equipment, and in order to cool the liquid crystal panel, etc., the cooling air is continuously ventilated, and in the case of obtaining a predetermined cooling temperature, it can also be a liquid cooling of the air injection pump and the cooling air. There are two dedicated and independent pumps for media drive.

In addition, according to the driving flow rate of the pump, cooling performance can be improved in the same way as the prior art cooling method.

Even if the object to be cooled is a heat-generating component other than the liquid crystal panel, the same nozzle can be added and arranged near the object to be cooled.

Furthermore, it is also applicable to electronic devices other than liquid crystal display devices requiring airtightness.

According to the cooling device of the embodiment of the present invention with the above-mentioned structure, it relates to the cooling of the high-temperature body of the liquid crystal display device that projects light. The heat and cooling generated by the liquid crystal panel or polarizing plate will not affect the picture quality, and the best liquid crystal display device that can provide the projected picture quality with a sense of visual uniformity.

Claims (5)

1. A cooling device for electronic equipment, characterized in that it has: The first cooling module cools the high-temperature body of the electronic device through the circulating first cooling medium; a second cooling module cooling the first cooling medium by circulating a second cooling medium; and A cooling medium driving module is driven to circulate the first cooling medium and the second cooling medium separately. 2. The cooling device for electronic equipment as claimed in claim 1, characterized in that: The first cooling medium is gas, and the first cooling module cools the high-temperature body by air cooling, The second cooling medium is liquid, and the second cooling module cools the first cooling medium by liquid cooling, The cooling medium drive module has a first pump chamber that discharges the first cooling medium and a second pump chamber that discharges the second cooling medium. 3. The cooling device for electronic equipment as claimed in claim 2, characterized in that: The first cooling module is arranged inside the airtight part of the electronic equipment provided with the high temperature body, In the second cooling module, the heat dissipation part is disposed outside the airtight part to cool the second cooling medium. 4. A cooling device for electronic equipment, characterized in that it has: The cooling medium driving module includes a first pump chamber for sucking in and discharging air and a second pumping chamber for sucking in and discharging coolant, and the first pumping chamber and the second pumping chamber act in linkage; The air cooling module includes: a nozzle that sprays cooling air toward a liquid crystal panel or a polarizer; and a heat exchange part that flows in air sucked and discharged through the first pump chamber and cools the air, while flowing out cooled air to the nozzle. Cooling air, the air cooling module is provided inside the airtight part of the electronic device with built-in liquid crystal panel and polarizer; and The liquid cooling module includes: a heat receiving part, cooling the heat exchange part through the cooling liquid sucked and discharged by the second pump chamber; outside the airtight part; and a pipeline connected in such a way that the cooling liquid circulates in the second pump chamber, the heat receiving part, and the heat dissipation part and circulates the cooling liquid. 5. The cooling device for electronic equipment as claimed in claim 4, characterized in that: Air ejection from the nozzles is performed at the field frequency of the liquid crystal panel or at a frequency synchronous with a submultiple frequency thereof.

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