JP5656262B2 - Cooling device, electronic apparatus equipped with cooling device, and liquid crystal projector - Google Patents

Description

  The present invention relates to cooling of a heating element in an electronic device.

  Conventionally, many means for cooling a heating element in an electronic device have been developed, some of which have been put into practical use. An air cooling type cooling means, which is one of these cooling means, is adopted in many electronic devices as a simple and inexpensive cooling means. For example, even in a projection display device (projector) that is widely used for business use and general home use, air-cooling, particularly forced air-cooling cooling means is employed.

  The projection display device is a display device that enlarges and projects an image generated on an image display element onto a screen. Among such projection display devices, a liquid crystal projector using a liquid crystal panel as an image display element enlarges and projects an image on a screen with the following configuration and operation.

  The liquid crystal projector includes a light source. White light emitted from the light source is reflected by a reflector, is polarized and converted by a PBS (Polarization Beam Splitter), and then separated into R / G / B color lights. Each separated color light is guided to a liquid crystal panel prepared for each color, and enters a corresponding liquid crystal panel. Each color light incident on the liquid crystal panel undergoes light modulation according to the video signal by the liquid crystal panel. The light-modulated color lights are synthesized by a color synthesis prism and projected onto a screen via a projection optical system.

  Here, the liquid crystal panel operating in the TN (Twisted Nematic) mode can handle only a specific linearly polarized light component. Accordingly, a polarizing plate is disposed on the incident side of each liquid crystal panel, and the polarization direction of the color light incident on the liquid crystal panel is unified to a predetermined direction (here, it is assumed that the polarization is unified to S-polarized light). Further, a polarizing plate is also disposed on the exit side of the liquid crystal panel, and the S-polarized component of the light modulated by the liquid crystal panel is cut by the polarizing plate, and only the P-polarized component is extracted. Here, it is normal that the liquid crystal panel and the polarizing plates arranged before and after the liquid crystal panel are integrated to form a unit (liquid crystal unit). In the following description, the polarizing plate disposed on the incident side of the liquid crystal panel may be referred to as “incident side polarizing plate”, and the polarizing plate disposed on the output side may be referred to as “exit side polarizing plate”.

  As described above, the incident-side polarizing plate and the outgoing-side polarizing plate arranged along the optical axis before and after the liquid crystal panel allow only polarized light in one axis direction to pass through and shield the other polarized light. The light shielded by the incident side polarizing plate and the outgoing side polarizing plate is converted into heat. That is, the incident side polarizing plate and the outgoing side polarizing plate generate heat. Also in the liquid crystal panel, a part of incident light is shielded by a black matrix at each pixel boundary, and the shielded light is converted into heat. Therefore, the liquid crystal panel generates heat similarly to the incident side polarizing plate and the outgoing side polarizing plate. In other words, the liquid crystal unit is a heating element in an electronic device called a projector.

  On the other hand, organic materials are often used for liquid crystal panels and polarizing plates. Therefore, when irradiated with light having a short wavelength for a long time or exposed to a high temperature, the alignment film of the liquid crystal panel is damaged, or the polarization selection characteristic of the polarizing plate is deteriorated. It will be. Therefore, the liquid crystal projector is provided with a cooling means for cooling the liquid crystal unit. Hereinafter, the cooling means provided in the liquid crystal projector will be described in detail.

  FIG. 19A is an external perspective view of a general liquid crystal projector 1, and FIG. 19B is a perspective view showing the internal structure. FIG. 20 is a plan view schematically showing the internal structure shown in FIG.

  As shown mainly in FIG. 20, a cooling fan 3 and an air cooling duct 4 for forced air cooling of the liquid crystal unit 2 are provided in the casing of the liquid crystal projector 1. Further, a cooling fan 7 for forcibly cooling the light source 5 is provided. In addition, an exhaust fan 8 is provided for forcibly exhausting air in the housing to cool the power supply unit 6 and the like.

  With reference to FIG. 21, the cooling effect | action of the liquid crystal unit 2 by the cooling fan 3 and the air cooling duct 4 is demonstrated concretely. FIG. 21A is an exploded perspective view of the cooling fan 3 and the air cooling duct 4, and FIG. 21B is a schematic diagram showing the flow of cooling air.

  As shown in FIGS. 21A and 21B, the liquid crystal unit 2 including the incident side polarizing plate 10, the liquid crystal panel 11, and the output side polarizing plate 12 is provided for each color light of R / G / B. The discharge port 15 of the air cooling duct 4 is arranged below the liquid crystal unit group.

  As shown mainly in FIG. 21 (b), the cooling air 14 generated by the cooling fan 3 blows out from the discharge port 15 through the air cooling duct 4. The cooling air 14 blown out from the discharge ports 15 is supplied to the liquid crystal units 2 from below the liquid crystal units 2. The cooling air 14 supplied to each liquid crystal unit 2 passes through the space between the incident side polarizing plate 10, the liquid crystal panel 11 and the outgoing side polarizing plate 12 of each unit 2 and escapes upward.

  Here, with the recent diversification of projector usage, there is an increasing demand for miniaturization and high brightness. In order to meet such demands, improvements in lamp output and downsizing of display devices (liquid crystal units) are being promoted. As a result, the light flux density of light incident on the liquid crystal unit is increased, and the thermal loads of the liquid crystal panel, the incident-side polarizing plate, and the outgoing-side polarizing plate constituting the liquid crystal unit are constantly increasing.

  On the other hand, for the purpose of reducing the environmental load and running cost, there is a growing demand for longer projector life. Except for the lamp replacement part, the life of the liquid crystal projector mainly depends on the life of the liquid crystal unit. If the life of the liquid crystal unit can be extended by increasing the cooling capacity of the cooling means of the liquid crystal unit, the life of the liquid crystal projector itself can be extended.

  In general, when an air cooling method is employed as a cooling means for a liquid crystal unit, in order to increase the cooling capacity, it is necessary to increase the air flow rate of the cooling fan and increase the air velocity of the cooling air. However, when the rotational speed of the cooling fan is increased to increase the air flow rate, the operation noise of the cooling fan also increases. Further, when the diameter of the cooling fan is increased to increase the air flow rate, the size of the device is increased.

  Further, when the cooling air is a laminar flow flowing in parallel along the cooling target, the average heat transfer coefficient is proportional to the square root of the wind speed, and the temperature rise of the cooling target is inversely proportional to the square root of the wind speed. Therefore, when the temperature of the cooling target is reduced to a certain level, the sensitivity of the temperature reduction of the cooling target with respect to the increase in the wind speed becomes dull.

  FIG. 22 shows an example of the wind speed dependence curve of the operating temperature of a 0.8 "size liquid crystal panel (5000 lm-25 ° C. environment). FIG. 22 shows that the liquid crystal panel operating temperature is lowered from 70 ° C. to 60 ° C. It is only necessary to increase the cooling wind speed from 4.5 m / s to 8.0 m / s. However, when the cooling wind speed is decreased from 60 ° C. to 50 ° C., the cooling wind speed is changed from 8.0 m / s to 18.m. It can be seen that the speed must be increased to 0 m / s.

  Therefore, in order to extend the life of the liquid crystal unit, when aiming to further reduce the operating temperature of the liquid crystal unit (particularly the operating temperature of the liquid crystal panel), it is necessary to extremely increase the speed of the cooling air. However, as described above, when the speed of the cooling air is increased, the operation noise of the cooling fan may increase and the size of the apparatus may increase. Furthermore, even if an increase in the operating noise of the cooling fan and an increase in the size of the apparatus are allowed, there is a limit (air cooling limit) in improving the cooling capacity.

  Further, regarding the liquid crystal panel, there is another requirement for cooling from the viewpoint of image quality. In the light modulation in the liquid crystal panel, the temperature dependency of the light modulation effect on the input signal is high. Therefore, when temperature unevenness occurs on the panel surface, brightness unevenness and color unevenness occur, and image quality deteriorates. Therefore, regarding the cooling of the liquid crystal panel, a cooling method that minimizes the temperature gradient and temperature unevenness generated on the panel surface is desired.

  Until now, cooling of electronic devices has been described by taking a projector, particularly a liquid crystal projector as an example. However, in addition to projectors, there are a large number of electronic devices having heating elements, and efficient cooling means are required as performance of the electronic devices is improved and usage modes are diversified. For example, a recent personal computer incorporates a high-performance central processing unit, and the central processing unit generates heat during its operation. On the other hand, in order to ensure stable operation of the central processing unit, it is necessary to cool the processing unit and maintain the operating temperature within a predetermined range.

  Under the circumstances as described above, there is an urgent need to develop a means for cooling the heating element of the electronic device with high efficiency. Therefore, Patent Document 1 discloses a structure aimed at improving the cooling efficiency of the liquid crystal panel by adjusting the direction of the cooling air blown to the liquid crystal panel. Specifically, as shown in FIG. 23, there is disclosed a structure in which a wind direction plate 17 is provided below the color synthesis prism 16, and the direction of the cooling air 14 sent out from the cooling fan 3 by the wind direction plate 17 is controlled. Yes. According to Patent Document 1, the direction of the cooling air 14 is optimized by the wind direction plate 17.

  Patent Document 2 discloses a structure for supplying cooling air for cooling the liquid crystal panel to the liquid crystal panel without waste. Specifically, as shown in FIG. 24, the cooling frame 18 is a holding frame 18 that holds the liquid crystal panel 11, and guides cooling air sent from a duct discharge port 20 provided below the liquid crystal panel 11 to the liquid crystal panel 11. A holding frame 18 having a projecting piece 19 is disclosed. According to Patent Document 2, the cooling air sent out from the duct discharge port 20 is guided to the liquid crystal panel 11 by the projecting piece portion 19 almost without leakage, so that the cooling efficiency is improved.

  Patent Document 3 discloses a structure for securing a sufficient ventilation area even when the distance between the holding frame holding the liquid crystal panel and the polarizing plate is narrow. Specifically, as shown in FIG. 25, a notch 21 is provided in the ventilation path of the holding frame 18 of the liquid crystal panel 11, and the width of the ventilation path between the liquid crystal panel 11 and the emission side polarizing plate 12 (in the figure: The structure which changed X part and Y part) is disclosed. According to Patent Document 3, the air blowing speed is improved by the above structure.

  Patent Document 4 discloses a structure that aims to alleviate panel temperature unevenness by reversing the air blowing direction between the incident side surface and the exit side surface of a liquid crystal panel. Specifically, as shown in FIG. 26, a U-shaped air guide path 22 is provided between the liquid crystal panel 11 and the polarizing plate 10 arranged around the color synthesis prism 16 to make U-turn the cooling air. Thus, a structure is disclosed in which the direction of air flow is reversed between the incident side surface and the output side surface of the liquid crystal panel 11. Further, in Patent Document 4, as shown in FIG. 27, a pair of cooling fans 3a and 3b are provided above and below the liquid crystal panel 11, with the liquid crystal panel 11 being sandwiched therebetween, and the emission side is from the lower side to the upper side. Discloses a structure for sending air from above to below.

JP-A-11-295814 JP 2001-318361 A JP 2004-61894 A JP 2000-124649 A

  According to the structure disclosed in Patent Document 1, it is possible to increase the amount of cooling air that strikes the exit surface of the liquid crystal panel. However, the amount of cooling air striking the exit-side polarizing plate facing the exit surface of the liquid crystal panel is conversely suppressed, and the cooling efficiency of the exit-side polarizing plate is deteriorated.

  As disclosed in Patent Document 2, if the leakage of the cooling air is suppressed by the projecting piece provided on the holding frame of the liquid crystal panel, the reduction of the wind speed due to the increase of the ventilation resistance and the exhaust heat in the downstream area (upper part of the liquid crystal panel). Panel temperature rises due to stagnation (exhaust exhaust deterioration). Therefore, the improvement in cooling efficiency is offset and it is difficult to obtain a sufficient effect as a whole.

  As disclosed in Patent Document 3, even if a notch is provided on the downstream side of the ventilation path to increase the ventilation area, the wind speed of the cooled part (the light transmission surface of the liquid crystal panel or polarizing plate) is reduced. The improvement in cooling efficiency cannot be expected. In addition, when the interval between the inflow side end portions of the ventilation path (the interval between the units) is narrow, it becomes a ventilation resistance and the ventilation amount decreases, so that the improvement of the cooling efficiency cannot be expected.

  As disclosed in Patent Document 4, when the cooling air is turned back by the U-shaped groove-shaped ventilation path, the ventilation area is halved and the ventilation distance is doubled. Therefore, ventilation resistance increases and the amount of ventilation is suppressed. In addition, the temperature of the cooling air that has cooled the panel exit side surface in the first half of the U-shaped groove-shaped ventilation path is increased by heat exchange, and the cooling capacity is significantly reduced. Therefore, even if such cooling air is U-turned and guided to the panel incident side surface, high cooling efficiency cannot be expected.

  When cooling air flowing in opposite directions is supplied to the incident side surface and the output side surface of the liquid crystal panel by a pair of cooling fans (in the case of FIG. 27), the heat generation distribution (cooling action) on the panel surface is the incident side and the output side. And upside down. Therefore, the structure shown in FIG. 27 can be expected to have a certain effect from the viewpoint of achieving uniform temperature inside the panel. However, the cooling method follows the conventional cooling method in that it is cooled by applying a parallel flow to the heat generation surface, and the heat radiation load per fan is reduced while each ventilation area is halved. However, sufficient cooling efficiency cannot be obtained.

  The present invention has been made in view of the above problems, and an object thereof is to solve at least one of the above problems.

  In forced air cooling of flat heating elements (heating plates) such as polarizing plates, liquid crystal panels, and substrates with electronic components mounted, the method of improving heat transfer and promoting heat transfer is replaced with the thin film method. Two approaches of law are conceivable.

  The thinning method is a method of improving the heat transfer coefficient by thinning (thinning) the temperature boundary layer formed on the surface of the heating element. In this case, the thickness of the temperature boundary layer is inversely proportional to the square root of the velocity in the main flow direction (flow velocity along the flat plate). That is, as described above, the method of increasing the wind speed and decreasing the temperature of the heating element is based on the thinning method.

  The replacement method is a method that improves the heat transfer coefficient by facilitating the exchange (temperature replacement) between the fluid near the solid surface and the fluid at a slightly distant position. Use turbulent flow to promote heat transfer.

The present invention aims to achieve the above object by an approach based on a substitution method among the above two approaches. The present invention is characterized by comprising means for turning the direction of the cooling air sent from one generation source and passing through the space where the heating element exists in a direction different from the inflow direction. Specifically, cooling air generating means for generating cooling air, supply means for causing the cooling air to flow into the space, inhibition of the progress of the cooling air that has passed through the space, and direction of the cooling air And a wind-shielding means for changing the direction into the direction different from the direction of inflow into the space. The wind shielding means includes a block surface portion disposed so as to block a side surface opposite to the side surface of the heating element facing the supply unit, and another side surface of the heating element in contact with the opposite side surface. And a bottom surface portion arranged so as to be closed. The different orientation is mainly above the liquid crystal unit.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling device with high cooling efficiency although it is small, and an electronic device provided with it can be implement | achieved at low cost.

It is a conceptual diagram of collision jet cooling. It is a figure which shows the structure of a liquid crystal unit, (a) is a top view, (b) is a side view. It is explanatory drawing which shows the cooling principle of the cooling device which concerns on Embodiment 1. FIG. It is explanatory drawing which shows the cooling principle of the cooling device which concerns on Embodiment 2. FIG. (A) is sectional drawing which shows a part of internal structure of the liquid crystal projector provided with the cooling device based on Example 1, (b) is the elements on larger scale of (a), (c) is a flow of cooling air typically. FIG. (A) and (b) are the perspective views of the liquid crystal unit of the liquid crystal projector provided with the cooling device based on Example 1, and its vicinity, (c) is a perspective view of a baffle plate. 6 is a schematic cross-sectional view illustrating a configuration of a cooling device according to Embodiment 2. FIG. FIG. 8 is a perspective view of the liquid crystal unit and the air guide plate shown in FIG. 7. 6 is a schematic cross-sectional view illustrating a configuration of a cooling device according to Embodiment 3. FIG. 6 is a schematic cross-sectional view showing a configuration of a cooling device according to Example 4. FIG. FIG. 10 is a schematic cross-sectional view illustrating a configuration of a cooling device according to a fifth embodiment. FIG. 10 is a schematic cross-sectional view showing a configuration of a cooling device according to Example 6. FIG. 10 is a schematic cross-sectional view illustrating a configuration of a cooling device according to Example 7. It is a perspective view of the baffle plate of the cooling device concerning Example 8. (A) is sectional drawing which shows the flow of the cooling wind at the time of using the cooling device based on Example 8, (b) is sectional drawing which shows the modification of an air guide plate. (A) is sectional drawing which shows a part of internal structure of the liquid crystal projector provided with the cooling device based on Example 9, (b) is the elements on larger scale of (a), (c) is a flow of cooling air typically FIG. (A) is sectional drawing which shows a part of internal structure of the liquid crystal projector provided with the cooling device based on Example 10, (b) is the elements on larger scale of (a), (c) is a flow of cooling air typically. FIG. (A) and (b) are the perspective views of the liquid crystal unit of the liquid crystal projector provided with the cooling device based on Example 10, and its vicinity, (c) is a perspective view of a windshield. It is a perspective view which shows the external appearance and internal structure of a general liquid crystal projector. It is a schematic diagram which shows the internal structure of a general liquid crystal projector. (A) is an exploded view of the cooling fan and air cooling duct shown in FIG. 20, and (b) is a schematic diagram showing the flow of cooling air in the conventional cooling device. It is a figure which shows the relationship between the speed of the cooling air supplied to a liquid crystal panel, and operating temperature. It is a schematic diagram which shows the structure currently disclosed by patent document 1. FIG. It is a schematic diagram which shows the structure currently disclosed by patent document 2. FIG. It is a schematic diagram which shows the structure currently disclosed by patent document 3. FIG. FIG. 10 is a schematic diagram showing one of the structures disclosed in Patent Document 4. FIG. 10 is a schematic diagram showing another one of the structures disclosed in Patent Document 4.

(Embodiment 1)
Hereinafter, an example of an embodiment of a cooling device according to the present invention will be described by taking as an example a case where a cooling target is a liquid crystal unit built in a liquid crystal projector.

The cooling device according to the present embodiment cools an object to be cooled using a collision jet. Here, the impinging jet cooling is a method of cooling the heat generating surface by applying the jet B emitted from the nozzle A perpendicularly to the heat generating flat plate C as shown in FIG. In impinging jet cooling,
(1) Destruction of the temperature boundary layer on the heating surface due to jet collision (separation)
(2) Fluid exchange by swirl flow generated at the impingement part (temperature replacement)
(3) The heat is dissipated through a process such as wall surface slippage of the jet due to the Coanda effect. Therefore, the cooling performance is 5 to 10 times that of the cooling method in which the cooling air is blown along the heat generating flat plate. The Coanda effect is a property of a fluid in which when an object is placed in a fluid, the pressure between the fluid and the solid wall decreases, the flow is sucked to the wall surface, and the flow direction changes along the object. Say.

  By the way, when the above-described collision jet cooling is applied to a plurality of heat generating flat plates arranged in parallel so that the in-plane directions are the same, the jet collision method becomes a problem. For example, as shown in FIGS. 2A and 2B, in the case of the liquid crystal unit 20 in which the incident side polarizing plate 21, the liquid crystal panel 22, and the output side polarizing plate 23 are arranged in parallel along the optical axis, 23 and each heat generating surface of the liquid crystal panel 22 substantially coincide with the light transmitting surface 24. Therefore, it is necessary to generate a vertical air flow to the heat generating surface so as not to inhibit the transmission of each color light.

  Therefore, in the cooling device according to the present embodiment, as shown in FIGS. 3A and 3B, in the in-plane direction of the liquid crystal unit 20 based on the cooling air sent from one cooling fan (not shown). Means are provided for generating a first cooling air 31 flowing along and a second cooling air 32 flowing in a different direction from the first cooling air 31 along the in-plane direction of the liquid crystal unit 20. The two cooling airs 31 and 32 generated by such means are in the space (incident side space) between the liquid crystal panel 22 and the incident side polarizing plate 21 and the space between the liquid crystal panel 22 and the outgoing side polarizing plate 23. Collide in (exit side space). Then, the swirl | flow which goes perpendicularly | vertically to the heat generating surface which opposes generate | occur | produces, a vertical jet is formed, a heat transfer rate increases, and heat transfer promotion is aimed at.

  Next, another example of the embodiment of the cooling device of the present invention will be described by taking as an example the case where the object to be cooled is a liquid crystal unit. The structure of the liquid crystal unit that is the cooling target of the cooling device according to the present embodiment is the same as the liquid crystal unit 20 (FIG. 2) that is the cooling target of the cooling device according to the first embodiment. Therefore, the same reference numerals are used for the liquid crystal unit.

  As shown in FIG. 4, the cooling device according to the present embodiment sends the cooling air 40 sent from one cooling fan (not shown) and passed through the incident side space and the emission side space in a direction different from the inflow direction. A means for forcibly turning is provided. By turning the direction of the cooling air 40 by such means, a swirl flow corresponding to the amount of change in the velocity vector is generated in the vicinity of the turning position, and the turbulent flow effect in each space between the liquid crystal panel 22 and the polarizing plate is enhanced. Heat transfer is promoted. In addition, cooling air is exhausted using wall surface slippage due to the Coanda effect.

  Hereinafter, the cooling device according to Embodiment 1 and Embodiment 2 will be described in more detail with some examples. The following Examples 1 to 8 are examples of the cooling device according to the first embodiment, and Examples 9 and 10 are examples of the cooling device according to the second embodiment. In all the embodiments, the object to be cooled is three liquid crystal units provided in the liquid crystal projector, and the structure of each liquid crystal unit is as shown in FIG. However, in the drawings referred to in the following description, only one liquid crystal unit is shown for convenience.

Example 1
5 and 6 are schematic views showing a part of the internal structure of a liquid crystal projector provided with the cooling device of this example. Specifically, FIG. 5A is a cross-sectional view showing the cooling device and the structure in the vicinity thereof, FIG. 5B is a partially enlarged view of FIG. 5A, and FIG. 5C shows the flow of cooling air. It is sectional drawing shown. FIGS. 6A and 6B are perspective views showing the liquid crystal unit and the structure in the vicinity thereof, and FIG. 6C is a perspective view of the air guide plate.

  As shown mainly in FIGS. 5A and 6A, the cooling device of this example includes a cooling fan 50, an air cooling duct 51, and an air guide plate 52. The cooling fan 50 and the air cooling duct 51 are disposed below the liquid crystal unit group including the liquid crystal unit 20 illustrated, and the air guide plate 52 is disposed on the side of each liquid crystal unit including the liquid crystal unit 20. Yes. The air cooling duct 51 is provided with two discharge ports 51a and 51b that open below the liquid crystal unit group. Further, the air guide plate 52 is provided with an inclined surface 52a that is inclined in a direction close to the corresponding liquid crystal unit.

  A part of the cooling air 53 generated by the cooling fan 50 is discharged from the discharge port 51 a of the air cooling duct 51 toward each liquid crystal unit including the liquid crystal unit 20. On the other hand, the other part of the cooling air 53 generated by the cooling fan 50 is discharged from the discharge port 51 b of the air cooling duct 51 toward the air guide plate corresponding to each liquid crystal unit including the air guide plate 52. That is, the cooling air 53 generated by the cooling fan 50 is discharged by the air cooling duct 51 toward the respective liquid crystal units, and the second cooling air discharged toward the respective air guide plates. Branches to the wind 53b. In other words, the air cooling duct 51 functions as a branching unit that branches the cooling air 53 generated by the cooling fan 50 into the first cooling air 53a and the second cooling air 53b.

  Next, with reference to FIGS. 5B and 5C, the cooling action by the cooling device of this example will be described. Here, the cooling action will be described by taking the liquid crystal unit 20 as an example, but the cooling action for other liquid crystal units is also the same.

  The first cooling air 53a branched as described above flows into the spaces A and B from the opening surfaces (first opening surfaces) at the lower ends of the incident side space A and the emission side space B. , B flows from the lower side to the upper side in FIGS. 5 (b) and 5 (c). On the other hand, the second cooling air 53b is a wind guide plate 52 (particularly, a wind guide plate) disposed at a position facing the side opening surfaces (second opening surfaces) of the incident side space A and the emission side space B. The wind direction is changed by 90 degrees by an inclined surface 52 a) provided on the plate 52. The second cooling air 53b whose wind direction is turned flows into the incident side space A and the emission side space B from the second opening surface. That is, the air guide plate 52 changes the direction of the second cooling air 53b, is parallel to the surface of the liquid crystal panel, and is different from the first cooling air 53a in the incident side space A and the output side space. It functions as a turning means for flowing into B.

  The second cooling air 53b flowing into the incident side space A and the emission side space B by the action of the air guide plate 52 flows in the spaces A and B from the right side to the left side in FIG. A pair of side walls 52b are provided on both sides of the inclined surface 52a provided on the air guide plate 52 so as to prevent the second cooling air 53b from leaking. Has a hood-like form as a whole (FIG. 6C).

  As described above, the first cooling air 53a and the second cooling air 53b that flow into the incident-side space A and the emission-side space B from directions orthogonal to each other are in an orthogonal state at a substantially central position of each space. collide. At this time, the first cooling air 53a and the second cooling air 53b colliding from directions orthogonal to each other transmit light through the incident-side polarizing plate 21, the liquid crystal panel 22, and the emitting-side polarizing plate 23 at the collision position. A swirling flow directed vertically to the surface 24 (FIG. 2) is generated (see FIG. 5C). As a result, a vertical jet to the heat generating surface (light transmission surface 24) is formed, and the heat transfer coefficient in the vicinity of the heat generating element is greatly increased. Therefore, compared with the conventional cooling method using parallel plate flow, the heat radiation efficiency is greatly improved.

(Example 2)
FIG. 7A is a longitudinal sectional view schematically showing the structure of the cooling device of this example, and FIG. 7B is a transverse sectional view. FIG. 8 is a perspective view showing the structure of the liquid crystal unit and its vicinity.

  The basic configuration of the cooling device of this example is the same as that of the cooling device of the first embodiment. One of the differences is that air guide plates are provided on the left and right of each liquid crystal unit. Another one of the differences is that the discharge port of the air cooling duct is added along with the addition of the air guide plate. This will be specifically described below.

  As shown in FIG. 7A, the pair of air guide plates 62a and 62b are arranged in line symmetry with the longitudinal center axis YY of the liquid crystal unit 20 as the symmetry axis. The shapes and dimensions of the air guide plates 62a and 62b are the same as those of the air guide plate 52 described in the first embodiment. Specifically, as shown in FIG. 8, the air guide plates 62 a and 62 b include slopes for smoothly turning the flow direction of the cooling air that has flowed in, and side walls for preventing leakage of the cooling air. It has a hood-like form. Further, the width (W) of the air guide plates 62a and 62b is approximately the same as the length (L) of the liquid crystal unit 20 in the optical axis direction and is constant. In FIG. 8, the illustration of the one air guide plate 62b is omitted. In the following description, in FIG. 7A, the air guide plate 62a disposed on the right side (position facing the second opening surface) of the liquid crystal unit 20 is referred to as the “right air guide plate 62a” and the left side (above. The air guide plate 62b disposed at a position facing the third opening surface on the opposite side of the second opening surface is referred to as a “left air guide plate 62b” for distinction. However, such a distinction is merely a distinction for convenience of explanation.

  The air cooling duct 61 is provided with three discharge ports 61a, 61b, and 61c in order to branch the cooling air generated by a cooling fan (not shown) into three. A part of the cooling air generated by a cooling fan (not shown) is discharged toward the liquid crystal unit 20 from the discharge port 61a. The other part of the cooling air is discharged from the discharge port 61b toward the right air guide plate 62a. The other part of the cooling air is discharged from the discharge port 61c toward the left air guide plate 62b. That is, the cooling air generated by the cooling fan is discharged to the liquid crystal unit 20, the second cooling air 63b discharged toward the right air guide plate 62a, and the left air guide. It branches off to the third cooling air 63c discharged toward the air plate 62b.

  As shown in FIGS. 7 (a) and 7 (b), the first cooling air 63a and the second cooling air 63b whose wind direction is turned by the right air guide plate 62a are the incident side space A and the emission side space. Collisions in an orthogonal state at approximately the center of B. In addition, the first cooling air 63a and the third cooling air 63c whose air direction is turned by the left air guide plate 62b collide in an orthogonal state at substantially the center of the incident side space A and the emission side space B. Furthermore, the second cooling air 63b and the third cooling air 63c collide in an opposed state at substantially the center of the incident side space A and the output side space B.

  The first to third cooling winds 63 a, 63 b, 63 c that collide with each other in a direction orthogonal to or opposite to each other are perpendicular to the light transmission surfaces of the polarizing plates 21, 23 on the incident / exit side and the liquid crystal panel 22 at the collision position. Is generated, and a vertical jet flow to the heat generating surface (light transmitting surface) is formed.

  In the cooling device of the present embodiment, cooling air from three directions is caused to collide, so that a swirl flow with higher turbulence is formed and the cooling efficiency is further improved as compared with the cooling device of the first embodiment.

Example 3
FIG. 9 is a longitudinal sectional view schematically showing the structure of the cooling device of this example. The basic configuration of the cooling device of this example is the same as that of the cooling device of the second embodiment. The cooling device of this example is different from the cooling device of Example 2 in that one of the left and right air guide plates 62a and 62b shown in FIGS. 7A and 7B is set to the panel horizontal central axis XX of the liquid crystal unit 20. It is a point arranged at different heights as a reference. In this example, the left air guide plate 72b corresponding to the left air guide plate 62b shown in FIGS. 7A and 7B is displaced downward, and the right air guide plate 72a corresponding to the right air guide plate 62a is displaced upward. . More specifically, the left air guide plate 72b is displaced downward to a position where the upper end thereof coincides with the panel horizontal central axis XX. On the other hand, the right air guide plate 72a is displaced upward to a position where the vertical portion below the slope crosses the panel horizontal central axis XX.

  At this time, the first cooling air 73a discharged from the first discharge port 71a of the air cooling duct 71 and flowing from the lower side to the upper side in the incident side space and the output side space of the liquid crystal unit 20, and the third discharge port The third cooling air 73c discharged from 71c and flowing from the left side to the right side in the incident side space and the emission side space by the action of the left air guide plate 72b is a position below the panel horizontal central axis XX. Collide in an orthogonal state. As a result, the combined flow 74 generated by the collision between the first cooling air 73a and the third cooling air 73c and the second discharge port 71b are discharged, and the right air guide plate 72a acts to enter the incident side space. The second cooling air 73b flowing from the right side to the left side in the emission side space collides at an obtuse angle at a position above the panel horizontal central axis XX.

  Also in this case, the polarized light on the input / exit side at each of the collision position between the first cooling air 73a and the third cooling air 73c and the collision position between the combined flow 74 and the second cooling air 73b. A swirling flow directed vertically to the light transmission surface of the plate or the liquid crystal panel is generated, and a vertical jet flow to the heat generation surface (light transmission surface) is formed.

  The cooling device of this example is effective in eliminating temperature unevenness in a liquid crystal unit that employs a large (≧ 0.8 ″) liquid crystal panel or a wide liquid crystal panel (16: 9) wide on the left and right. Cooling air collides at two locations, the lower left and upper right, across the panel horizontal central axis XX in the incident side space and the output side space of the liquid crystal unit, and thus a wider range than the cooling device of the first embodiment. As a result, a swirling flow with high turbulence is formed, heat dissipation capability is improved, temperature distribution is made uniform, color unevenness is eliminated, and image quality is improved.

  It should be noted that the displacement direction and displacement amount of the left and right air guide plates 72a and 72b with respect to the panel horizontal central axis XX can be arbitrarily changed within a range in which the above-described action can be obtained.

Example 4
FIG. 10 is a longitudinal sectional view schematically showing the structure of the cooling device of this example. The basic configuration of the cooling device of this example is the same as that of the cooling device of the second embodiment. The cooling device of this example is different from the cooling device of Example 2 in that the air cooling duct 61 constituting the cooling device of Example 2 is provided with three discharge ports 61a, 61b, 61c (FIG. 7A). On the other hand, the air cooling duct 81 constituting the cooling device of this example is provided with only the discharge ports 81b and 81c corresponding to the discharge ports 61b and 61c. In other words, in the air cooling duct 81 constituting the cooling device of this example, the discharge port 61a of the air cooling duct 61 constituting the cooling device of the second embodiment is blocked.

  When the cooling device of the present example is used, the first cooling air 83a discharged from the discharge port 81b of the air cooling duct 81 and the direction of the wind being turned by the right air guide plate 82a is discharged from the right side to the left side in FIG. The second cooling air 83b discharged from 81c and turned in the direction of the wind by the left air guide plate 82b flows from the left side to the right side, and collides in an oblique state at the approximate center of each space. As a result, a swirl flow perpendicular to the heat generation surface (light transmission surface) of the liquid crystal unit 20 is generated in each space, and a vertical jet flow to the light transmission surface is formed.

  In the cooling device of this example, the cooling air generated by one cooling fan is branched into two systems to ensure sufficient air volume and air speed, and collide with it on the heat generation surface from the opposite direction of approximately 180 degrees. Thus, the turbulent flow generation effect of the jet flow is further enhanced, and the cooling capacity is improved.

  Note that the air guide plates 82a and 82b included in the cooling device of this example have curved surfaces corresponding to the inclined surfaces in the embodiments described above. However, such a difference is not an essential difference in the present invention. The shape of the air guide plate may be any shape that can turn the direction of the cooling air in a predetermined direction, and is not limited to a specific shape. It should be possible.

(Example 5)
FIG. 11 is a longitudinal sectional view schematically showing the structure of the cooling device of this example. The basic configuration of the cooling device of this example is the same as that of the cooling device of the third embodiment. The difference is that the air cooling duct 71 that constitutes the cooling device of the third embodiment is provided with three discharge ports 71a, 71b, 71c (FIG. 9), whereas the air cooling that constitutes the cooling device of this example. The duct 91 is provided with only discharge ports 91b and 91c corresponding to the discharge ports 71b and 71c. In other words, in the air cooling duct 91 constituting the cooling device of this example, the discharge port 71a of the air cooling duct 71 constituting the cooling device of the third embodiment is closed.

  In the cooling device of this example, in the incident side space and the emission side space of the liquid crystal unit 20, the first cooling air 93a whose wind direction is turned by the right air guide plate 92a is guided from the lower right to the upper left in FIG. The second cooling air 93b whose direction is turned by the wind plate 92b flows from the lower left to the upper right. Further, since the heights of the right air guide plate 92a and the left air guide plate 92b are different from each other (in this example, the right air guide plate 92a is more than the left air guide plate 92b on the basis of the panel horizontal central axis XX). The second cooling air 93b flowing from the lower left to the upper right in the incident side space and the outgoing side space becomes the first cooling air 93a flowing from the lower right to the upper left in the space. Collide vertically. As a result, a swirl flow perpendicular to the heat generating surface (light transmission surface) of the liquid crystal unit 20 is generated at the collision position in each space, and a vertical jet flow to the light transmission surface is formed. In other words, the first cooling air 93a is a barrier to the second cooling air 93b.

  In order to enhance the function of the first cooling air 93a as a barrier to the second cooling air 93b, the air volume of the first cooling air 93a may be made larger than the air volume of the second cooling air 93b. It is effective. Therefore, in this example, the opening area of the discharge port 91b of the air cooling duct 91 is made larger than that of the discharge port 91c, and the air volume of the first cooling air 93a is made larger than the air volume of the second cooling air 93b. .

  Here, in the cooling device of this example as well as in the cooling devices of other embodiments, it is preferable to appropriately adjust parameters for determining the turning direction of the cooling air, such as the inclination angle of the inclined surface of the air guide plate and the curvature of the curved surface. .

(Example 6)
FIG. 12 is a longitudinal sectional view schematically showing the structure of the cooling device of this example. The air cooling duct constituting the cooling device according to the embodiment described above was provided with two or more discharge ports, whereas the air cooling duct 101 constituting the cooling device of this example has only one discharge port 101a. Is provided.

  However, the opening area of the discharge port 101a of the air cooling duct 101 of this example is larger than the opening area of each discharge port of the air cooling duct described so far, and the opening center is larger than the panel vertical center axis YY. It is located near. Accordingly, a part of the cooling air discharged from the discharge port 101a hits the air guide plate 102 and the direction of the wind is turned to flow into the incident side space and the exit side space, and the other part directly enters the incident side space and the exit side space. Inflow. As a result, similar to the cooling device according to each of the embodiments described above, the cooling air flowing from the lower side to the upper side and the cooling air flowing from the right to the left in the incident side space and the emission side space are collided in an orthogonal state. Can do. That is, the air cooling duct 101 functions as a supply unit that causes a part of the cooling air generated by the cooling fan to flow into the entrance side space and the exit side space. On the other hand, the air guide plate 102 changes the direction of the other part of the cooling air generated by the cooling fan, is parallel to the surface of the liquid crystal panel, and directly flows into the incident side space and the output side space. It functions as a turning means for flowing into the spaces in a direction different from a part of the cooling air.

  The cooling device of the present embodiment is effective when a small liquid crystal panel (≦ 0.6 ″) is employed, and the liquid crystal unit and its cooling device are accordingly downsized. When the heating element is closer to the “point heat source”, the air cooling duct is also reduced in size accordingly. In such a case, it is preferable to use a structure in which cooling air is blown all at once rather than branching into two or more systems, and a part of the wind direction is controlled by a baffle plate. According to such a structure, a collision effect can be obtained with respect to the entire “point heat source”, and the entire heating element can be made highly turbulent at a higher wind speed, which is advantageous in increasing the cooling efficiency.

  If a cooling fan is arranged inside the air cooling duct and the cooling air generated from it is bent at right angles inside the air cooling duct and discharged upward from the discharge port, the discharge is discharged from the discharge port. Of the cooling air to be generated, the cooling air passing through the outer peripheral side of the bent portion in the air cooling duct has a higher wind speed than the cooling air passing through the inner peripheral side. Therefore, in this example, a high collision effect is obtained by providing the air guide plate 102 at the destination where the cooling air that has passed through the outer peripheral side of the bent portion in the air cooling duct 101 is discharged.

(Example 7)
FIG. 13 is a longitudinal sectional view schematically showing the structure of the cooling device of this example. Similarly to the cooling device according to the sixth embodiment, the cooling device of this example has one discharge port provided in the air cooling duct. The difference between the cooling device of this example and the cooling device according to Example 6 is that the opening width of the discharge port 111a provided in the air cooling duct 111 constituting the cooling device of this example is wider than the width of the liquid crystal unit 20. And the right air guide plate 112b and the left air guide plate 112b are provided on both sides of the liquid crystal unit 20. The right air guide plate 112a and the left air guide plate 112b are displaced in the vertical direction in the same manner as the right air guide plate 72a and the left air guide plate 72b constituting the cooling device according to the third embodiment (FIG. 9). Are arranged.

  Therefore, a part of the cooling air discharged from the discharge port 111a hits the right air guide plate 112a and the direction of the wind is turned to flow into the incident side space and the exit side space, and the other part directly enters the incident side space and the exit side space. The other part hits the left air guide plate 112b and the direction of the wind is turned to flow into the incident side space and the output side space.

  As described above, similarly to the cooling device according to the third embodiment, the collision position between the cooling air flowing from the lower side to the upper side in the incident side space and the outgoing side space and the cooling air flowing from the left to the right, and the combined flow and the incident In each of the collision positions with the cooling air flowing from the right to the left in the side space and the exit side space, a swirl flow perpendicular to the light transmission surface of the entrance and exit side polarizing plates and the liquid crystal panel is generated, generating heat. A vertical jet to the surface (light transmission surface) is formed.

  The cooling device of this example is also effective when a small liquid crystal panel (≦ 0.6 ″) is adopted and the liquid crystal unit and its cooling device are downsized in the same manner as the cooling device according to the sixth embodiment. The reason is the same as the reason described in the description of the sixth embodiment.

(Example 8)
FIG. 14 is a perspective view of the air guide plate 122 constituting the cooling device of this example. The basic configuration of the cooling device of this example is the same as that of the cooling device according to the second embodiment (FIG. 7). In FIG. 14, only one air guide plate 122 is shown, but actually, the air guide plate that forms a pair with the air guide plate 122 is disposed on the opposite side of the liquid crystal unit 20. That is, the number and arrangement relationship of the air guide plates are the same as the example shown in FIG.

  However, the upper part of the air guide plate 122 constituting the cooling device of the present example is narrowed so that the width (W2) on the cooling air outflow side is narrower than the width (W1) on the inflow side. Specifically, one upper part of the opposing side wall 122b is inclined so as to be close to the other. The inflow side width (W1) is approximately the same as the length (L) of the liquid crystal unit 20 in the optical axis direction.

  FIG. 15A is a cross-sectional view schematically showing the flow of cooling air sent into the incident side space A and the emission side space B by the cooling device of this example. As shown in the figure, the incident side space A is cooled only by the first cooling air 123a that is discharged from an outlet of an air cooling duct (not shown) and flows directly into the space A from below. On the other hand, the cooling of the emission side space B is performed by the first cooling air 123a, and the second cooling air 123b and the third cooling air 123c whose directions are turned by the air guide plates 122a and 122b. Here, the point that the three cooling airs 123a to 123c collide with each other in an orthogonal state or in an opposing state to form a swirling flow is the same as in Example 2 (see FIG. 7B). However, the width (W) of the air guide plates 62a and 62b constituting the cooling device of the second embodiment is constant (see FIG. 8). On the other hand, the widths of the air guide plates 122a and 122b constituting the cooling device of this example are reduced as described above. As a result, the amount and speed of the second cooling air 123b and the third cooling air 123c whose wind directions are turned by the air guide plates 122a and 122b are changed by the air guide plates 62a and 62b of the second embodiment. More than the second cooling air 63b and the third cooling air 63c (FIG. 7B). Therefore, a swirl flow having higher turbulence is generated in the exit side space B, and the cooling performance of the heat generating surface in the space B is greatly improved.

  Here, as shown in FIG. 15B, the directions of the apertures of the two air guide plates 122a and 122b can be reversed. In this case, a swirl flow having higher turbulence is generated in both the incident side space A and the exit side space B.

  According to the above configuration, it is possible to individually adjust the amount of cooling air colliding in the incident side space A or the emission side space B. Therefore, when the amount of cooling air flowing into each baffle plate becomes unbalanced due to the difference between the inner and outer circumferences of the wind speed caused by the bending of the air cooling duct, or when each member constituting the liquid crystal unit (incident side polarizing plate, liquid crystal It is possible to easily match the required cooling performance with the cooling performance that can be realized when the amount of heat generated by the panel and the output side polarizing plate is different.

  Here, the advantages of the cooling device of this example are described in comparison with the cooling device according to the second embodiment. However, the same effect as described above can be obtained by providing the above-described diaphragm on the air guide plate constituting the cooling device according to each of the embodiments described above.

Example 9
FIG. 16A is a schematic cross-sectional view showing a part of the internal structure of the liquid crystal projector provided with the cooling device of this example, and FIG. 16B is a partially enlarged view of FIG. . FIG. 16C is an explanatory diagram showing the principle of cooling by the cooling device of this example.

  As shown in FIG. 16A, the cooling device of this example includes a cooling fan 130, an air cooling duct 131, and a wind shielding plate 132. The air cooling duct 131 has a substantially L-shaped cross-sectional shape, and the discharge port 131 a for supplying cooling air to the liquid crystal unit 20 is disposed on the side of the liquid crystal unit 20. On the other hand, the wind shielding plate 132 has a substantially L-shaped cross-sectional shape, and is disposed on the opposite side of the discharge port 131a of the air cooling duct 131 with the liquid crystal unit 20 interposed therebetween. More specifically, as shown in FIG. 16B, the wind shield plate 132 has a horizontal surface (bottom surface 132a) that closes the lower end of the liquid crystal unit 20, and a surface that is orthogonal to the bottom surface 132a (block surface 132b). Is arranged so as to block the side surface opposite to the side surface of the liquid crystal unit 20 facing the discharge port 131a of the air cooling duct 131. FIG. 16 shows an example in which the discharge port 131a of the air cooling duct 131 is arranged on the left side of the drawing and the wind shielding plate 132 is arranged on the right side of the drawing, but the discharge port 131a of the air cooling duct 131 and the wind shielding plate 132 are shown. The positional relationship may be reversed left and right.

  Next, the cooling operation of the liquid crystal unit 20 by the cooling device of this example will be described. As shown in FIG. 16A, the cooling air 133 generated by the cooling fan 130 is discharged toward the liquid crystal unit 20 from the discharge port 131 a of the air cooling duct 131 prepared on the side of the liquid crystal unit 20. A portion of the discharged cooling air 133 flows into the incident side space and flows in the same space from the left side to the right side in FIG. On the other hand, the other part of the discharged cooling air 133 flows into the emission side space and flows from the left side to the right side in FIG. The air cooling duct 131 functions as a supply unit that causes the cooling air 133 to flow into the incident side space and the output side space in a direction parallel to the surface of the liquid crystal panel. In the following description, the cooling air flowing as described above in the entrance / exit side space of the liquid crystal unit 20 is referred to as “cross air blowing”.

  Crossing airflow that has passed through the entrance / exit side space collides with the block surface 132b of the wind shielding plate 132, and changes the wind direction along the surface of the block surface 132b. In other words, the wind shielding plate 132 functions as a wind shielding means that inhibits the progress of the cross air flow and changes the wind direction of the cross air flow in a direction different from the inflow direction of the cooling air into the entrance / exit side space. In the following description, the cooling air (cross air blowing) that collides with the block surface 132b and changes the air direction is referred to as “wall air blowing”.

  The behavior of the cooling air will be described with reference to FIG. When the jet 201 (cross air blow) discharged from the nozzle 200 corresponding to the discharge port 131a of the air cooling duct 131 collides with the wall surface 202 (block surface 132b of the wind shield plate 132), a stagnation region is formed at the collision portion. . A wall surface jet region that changes the wind direction along the wall surface 202 is formed in the peripheral region of the collision portion. This corresponds to the wall slip due to the Coanda effect described above. Specifically, a jet flow (so-called wall jet) that is forced to turn a velocity vector due to a collision with the wall surface 202 and flows along the wall surface (solid boundary) shows the maximum turbulence intensity in the vicinity of the stagnation point. On the other hand, as the distance from the distance increases, the flow velocity (UX) and the turbulent energy are weakened while the free shear layer (the region of action of the velocity distribution on the free space side by the wall jet) is expanded and flows. Moreover, the wall surface jet (wall surface air flow) that changes the direction by collision with the wall surface and forms the wall surface jet region generates a swirl flow having high turbulence and diffusibility in the vicinity of the turning position of the air flow vector. As described above, the collision jet cooling processes (2) and (3) described above are executed, and high cooling performance is obtained.

  Further, the cooling air guided to the block surface 132b of the wind shielding plate 132 by the wall slip cools the heating element (incident side polarizing plate, liquid crystal panel, and outgoing side polarizing plate), and then is sent out to the outside of the liquid crystal unit 20 as it is. Therefore, efficient exhaust heat treatment can be performed. At this time, since the flow of the wall surface sliding toward the lower side of the liquid crystal unit 20 is blocked by the bottom surface 132a of the wind shielding plate 132, the cooling air is exhausted (exhaust heat) mainly upward of the liquid crystal unit 20.

  As can be seen from the above description, in the cooling device of this example, in the vicinity of the position where the cooling air collides with the wind shielding plate, the cooling air is made turbulent to improve the heat transfer coefficient, and high cooling is achieved. Has gained performance. Therefore, it is desirable that the cooling device of this example is mainly applied to cooling of a liquid crystal unit in which a small liquid crystal panel is adopted and the heating element is close to a “point heat source”. It is possible to provide a high-efficiency cooling system with a low-cost, compact and simple configuration for equipment.

(Example 10)
17 and 18 are schematic views showing a part of the internal structure of the liquid crystal projector provided with the cooling device of this example. Specifically, FIG. 17 (a) is a cross-sectional view showing the cooling device and the structure in the vicinity thereof, FIG. 17 (b) is a partially enlarged view of FIG. 17 (a), and FIG. It is explanatory drawing shown. FIGS. 18A and 18B are perspective views showing the liquid crystal unit and the structure in the vicinity thereof, and FIG. 18C is a perspective view of the wind shielding plate.

  The basic configuration of the cooling device of this example is the same as that of the cooling device according to the ninth embodiment. The difference is that the cross-sectional shape of the wind shield plate 142 is substantially J-shaped, and a side wall facing the wind shield plate 142 is provided. Specifically, it has a bottom surface 142a corresponding to the bottom surface 132a of the wind shield plate 132 shown in FIG. 16, and a block surface 142b corresponding to the block surface 132b. However, the block surface 142b of the wind shielding plate 142 in this example is configured by a curved surface. In addition, a side wall 142c is provided between the bottom surface 142a and the block surface 142b so as to prevent leakage of cooling air.

  Next, the cooling operation of the liquid crystal unit 20 by the cooling device of this example will be described. As shown in FIG. 17A, the cooling air 143 generated by the cooling fan 140 is discharged toward the liquid crystal unit 20 from the discharge port 141 a of the air cooling duct 141 prepared on the side of the liquid crystal unit 20. A portion of the discharged cooling air 143 flows into the incident side space, and flows from the left side to the right side in FIG. On the other hand, the other part of the discharged cooling air 143 flows into the emission side space and flows from the left side to the right side in FIG. In the following description, the cooling air flowing as described above in the entrance / exit side space of the liquid crystal unit 20 is referred to as “cross air blowing”.

  Crossing airflow that has passed through the entrance / exit side space collides with the block surface 142b of the wind shielding plate 142, and changes the wind direction to an acute angle (θ) along the surface (curved surface) of the block surface 142b. In the following description, the cooling air that collides with the block surface 142b and changes the air direction is referred to as “wall air blowing”.

  Also in this case, the wall surface air blown by colliding with the block surface 142b and changing the wind direction generates a swirl vortex in the vicinity of the wind direction turning position, and exhibits high cooling performance due to the temperature replacement effect. This is the same as the cooling device according to the ninth embodiment. However, in the cooling device of this example in which the curvature is given to the block surface 142b of the wind shielding plate 142, the behavior of the cooling air is different from the cooling device according to the ninth embodiment.

  The behavior of the cooling air will be described with reference to FIG. When the jet 211 (transverse air blow) discharged from the nozzle 210 corresponding to the discharge port 141a of the air cooling duct 141 collides with the curved wall 212 (block surface 142b of the wind shield 142), it is formed by wall slip in the wall jet region. The jet flow (wall blow) is turned at an acute angle with respect to the jet (transverse blow) discharged from the nozzle 210 (contrast with FIG. 16 (c) and FIG. 17 (c)).

  By the way, the flow on the wall with curvature (curved channel turbulence) shows the flow characteristics that the turbulent intensity in the radial direction increases with the increase of the curvature (effect of streamline curvature of momentum in wall turbulence). .

  Therefore, when the wind direction is turned at a steep angle by making the block surface 142b of the wind shielding plate 142 into a curved surface as in this example, the turbulence intensity increases in the flow near the wind direction turning position (wall blow). It can be expected that high heat transfer characteristics can be obtained.

  Also in this example, as in the ninth embodiment, the air blowing toward the lower side of the liquid crystal unit 20 among the wall air blowing is blocked by the bottom surface 142 a of the wind shielding plate 142. Therefore, the air blowing vector is turned around and exhausted (exhaust heat) mainly toward the upper left of the liquid crystal unit 20.

20 Liquid crystal unit 21 Incident side polarizing plate 22 Liquid crystal panel 23 Outgoing side polarizing plate 51, 61, 71, 81, 91, 101, 111, 131, 141 Air cooling ducts 51a, 61a, 71a First discharge ports 51b, 61b, 71b Second discharge port 81b, 81c, 91b, 91c, 101a, 111a, 131a, 141a Discharge port 52, 102 Air guide plate 62a, 72a, 82a, 92a, 112a Right air guide plate 62b, 72b, 82b, 92b, 112b Left wind guide plate 132, 142 Wind shield plate

Claims (6)

A liquid crystal unit in which an incident-side polarizing plate and an outgoing-side polarizing plate are arranged opposite to each other with a liquid crystal panel interposed therebetween, an incident-side space between the liquid crystal panel and the incident-side polarizing plate, and the liquid crystal panel and the outgoing-side polarizing plate A cooling device for cooling the liquid crystal unit by supplying cooling air to the exit side space between the liquid crystal projector,
The cooling device is
Cooling air generating means for generating the cooling air;
Supply means for flowing the cooling air into the incident side space and the exit side space;
Wind shielding means for preventing the cooling air from passing through the incident side space and the emission side space and changing the direction of the cooling air to a direction different from the inflow direction to the incident side space and the emission side space; Have
The wind-shielding means is in contact with the opposite side surface and a block surface portion arranged to close the side surface opposite to the side surface of the liquid crystal unit facing the supply means. A bottom surface portion arranged to close the side surface ,
The different orientations, mainly, a liquid crystal projector, wherein the upper der Rukoto of the liquid crystal unit. The liquid crystal projector according to claim 1, wherein the block surface portion is a curved surface. 3. The liquid crystal projector according to claim 2, wherein the wind shielding means has a pair of side wall portions between the bottom surface portion and the block surface portion. The liquid crystal projector according to any one of claims 1 to 3, characterized in that said supply means is a duct for guiding the pre-Symbol cooling air to a predetermined position. A cooling method for a liquid crystal unit in which an incident-side polarizing plate and an outgoing-side polarizing plate are arranged to face each other with a liquid crystal panel interposed therebetween,
Cooling air is generated by the cooling air generating means,
The cooling air is allowed to flow into the incident side space between the liquid crystal panel and the incident side polarizing plate and into the outgoing side space between the liquid crystal panel and the outgoing side polarizing plate,
The incident side by the wind-shielding means for closing the side surface of the liquid crystal unit on the side from which the cooling air flows out and the other side surface of the liquid crystal unit on the side from which the cooling air flows out. The progress of the cooling air that has passed through the space and the emission side space is prevented, the cooling air is directed in a direction different from the direction of flowing into the incident side space and the emission side space, and the different directions are mainly the method of cooling a liquid crystal unit, wherein the upper der Rukoto of the liquid crystal unit. 6. The method of cooling a liquid crystal unit according to claim 5, wherein the cooling air is directed by the wind shielding means in a direction opposite to the other side surface of the liquid crystal unit.

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