JP5125877B2 - projector - Google Patents

Description

  The present invention relates to a projector, and more particularly to a technology of a projector that includes an ejector pump and cools a heat source.

  The light source device used for the projector is a very high temperature of, for example, 800 ° C. to 1000 ° C. Further, the projector is provided with an optical element that modulates the light emitted from the light source device. The optical element also generates heat when irradiated with light from the light source device, and reaches a temperature of room temperature or higher (eg, 60 ° C. to 90 ° C.). Therefore, in order to cool the light source device and the optical element, an air cooling type cooling method in which air is blown to the light source device or the like by a fan is used.

  Since the light source device is very hot, the temperature difference from the outside air becomes large. Therefore, the cooling efficiency can be increased only by blowing air of about room temperature onto the light source device. On the other hand, since the optical element is not as hot as the light source device, it is difficult to obtain high cooling efficiency even if air is blown in the same manner as the light source device.

  Increasing the air volume of the fan can increase the cooling efficiency of the optical element, but there is a problem that the operating noise of the fan increases with the increase of the air volume. Therefore, for example, Patent Document 1 proposes a technique of providing a cooling device including a compressor to increase the cooling efficiency of the optical element regardless of an increase in the air volume of the fan.

JP 2008-1112094 A

  However, if the projector is provided with a compressor, there arises a problem that the projector becomes large due to the installation space of the compressor. Further, there arises a problem that additional power is required to operate the compressor. The present invention has been made in view of the above-described problems, and can improve quietness and downsizing the apparatus, and can improve the cooling efficiency of a heat source such as an optical element while suppressing power consumption. An object is to provide a projector that can be used.

  In order to solve the above-described problems and achieve the object, a projector according to the present invention includes a light source unit that emits light and displays an image using light emitted from the light source unit, A heat-absorbing means for the light source that absorbs heat from the light source unit into the refrigerant; an ejector pump that allows the refrigerant that has absorbed heat by the heat-absorbing means for the light source to pass through; An evaporator that evaporates and cools the refrigerant, and absorbs heat from a heat source other than the light source into the refrigerant cooled by the evaporator, and the ejector pump absorbs heat by the heat absorbing means for the light source. The inside of the evaporator is depressurized by the pressure drop caused by the passage of.

  Since the refrigerant cooled by the evaporator absorbs heat from the heat source other than the light source unit, the cooling fan that cools the heat source other than the light source unit can reduce the air volume. In some cases, a cooling fan for cooling a heat source other than the light source unit can be eliminated. Accordingly, it is possible to suppress the operation noise of the cooling fan and improve the silence of the projector. In addition, the refrigerant inside the evaporator is deprived of heat of vaporization during evaporation and cooled.

  Since the inside of the evaporator is decompressed by the ejector pump, the boiling temperature of the refrigerant inside the evaporator can be lowered. Therefore, even if the temperature around the evaporator is about room temperature, the temperature of the refrigerant inside the evaporator can be lowered from the room temperature. By cooling using a temperature lower than room temperature, it is possible to cool the temperature of the heat source other than the light source unit lower than the conventional air cooling using the air in the casing of about room temperature.

  Since the low temperature is generated by the decompression of the inside of the evaporator by the ejector pump, the power consumption can be suppressed as compared with the case of using the cooling device provided with the compressor. Further, the ejector pump is easier to miniaturize than the compressor, and can contribute to the miniaturization of the projector itself.

  Since the refrigerant that absorbs heat from the light source is passed through the ejector pump to reduce the pressure inside the evaporator, there is no need to install a compressor to reduce the pressure inside the evaporator, and the size of the device is reduced. And power consumption can be reduced.

  Moreover, as a preferable aspect of the present invention, it is desirable to evaporate the refrigerant in the heat absorbing means for the light source. The refrigerant evaporates in the heat absorbing means for the light source to become a gas phase refrigerant. The gas-phase refrigerant is easier to pass through the ejector pump at a higher speed than the liquid-phase refrigerant. Since the ejector pump can increase the pressure drop as the velocity of the fluid passing through the inside increases, it is easy to reduce the pressure inside the evaporator by evaporating the refrigerant in the heat absorbing means for the light source. If the pressure inside the evaporator is reduced to a pressure at which the boiling temperature of the refrigerant becomes room temperature or lower, the temperature of the refrigerant inside the evaporator can be cooled to room temperature or lower.

  In a preferred aspect of the present invention, the heat source is preferably an optical element that modulates light emitted from the light source unit. The optical element is easily deteriorated by a temperature rise. The temperature of the optical element rises when irradiated with light emitted from the light source, but the life of the product is prevented by absorbing the heat from the optical element in the refrigerant cooled inside the evaporator, preventing the temperature of the optical element from rising. Can be extended.

  Moreover, as a preferable aspect of the present invention, it is desirable to further include a heat pipe surrounding the periphery of the optical element, and a part of the heat pipe is fixed to the evaporator to perform heat exchange.

  The optical element can be uniformly cooled from the surroundings by a heat pipe surrounding the optical element. Therefore, it is possible to prevent the optical element from deteriorating locally by eliminating uneven cooling of the optical element.

  As a preferred embodiment of the present invention, the optical element is preferably arranged in contact with the evaporator. Since the optical element is disposed in contact with the evaporator, the heat from the optical element can be directly absorbed by the refrigerant inside the evaporator. Therefore, since a special component for absorbing the heat from the optical element by the refrigerant inside the evaporator is not necessary, a small and simple configuration can be achieved.

  Further, as a preferred aspect of the present invention, an optical element heat absorbing means for absorbing heat from the optical element by the refrigerant flowing separately from the refrigerant in the evaporator, and an optical element disposed inside the evaporator It is desirable to provide a pipe through which the refrigerant having absorbed heat by the heat absorbing means is passed.

  The refrigerant that flows separately from the refrigerant in the evaporator absorbs heat from the optical element and passes through the piping disposed in the evaporator, so that the refrigerant that flows separately from the refrigerant in the evaporator The heat absorbed from the optical element can be absorbed by the refrigerant inside the evaporator.

  For the piping of the evaporator system in which the gas-phase refrigerant exists, a metal tube is often used in which the gas-phase refrigerant is difficult to dissipate out of the piping. On the other hand, most of the refrigerant separated from the refrigerant in the evaporator is composed of a liquid-phase refrigerant. Therefore, the pipe that allows the refrigerant that has absorbed heat by the heat absorbing means for optical elements to pass therethrough is made of a material different from that of the metal pipe. Can be used. For example, if a pipe made of an easy material such as a bending process is used, it is easy to configure a free pipe path in accordance with the position of the optical element and the like, and the design flexibility of the projector can be increased.

  Moreover, as a preferable aspect of the present invention, it is desirable that the heat absorbing means for optical elements and the pipe are connected by a flexible tube. Since the optical element heat absorption means and the pipe are connected by a flexible tube, only the optical element heat absorption means can be moved without moving the evaporator or the like. Even when the optical element and the heat absorbing means for the optical element are integrated, fine adjustment of the arrangement position of the optical element can be easily performed.

  Further, as a preferred aspect of the present invention, the heat absorbing means for the optical element includes a heat pipe surrounding the periphery of the optical element, and a part of the heat pipe is cooled by the flowing refrigerant separated from the refrigerant in the evaporator. It is preferable.

  The optical element can be uniformly cooled from the surroundings by a heat pipe surrounding the optical element. Therefore, it is possible to prevent the optical element from deteriorating locally by eliminating uneven cooling of the optical element. Further, since most of the refrigerant separated from the refrigerant in the evaporator is composed of a liquid-phase refrigerant, the pipe through which the refrigerant having absorbed heat by the heat absorbing means for the optical element passes is made of a material different from that of the metal pipe. Piping can be used. For example, if a pipe made of an easy material such as a bending process is used, it is easy to configure a free pipe path in accordance with the position of the optical element and the like, and the design flexibility of the projector can be increased.

  Moreover, as a preferable aspect of the present invention, the heat-absorbing means for the light source includes a first surface that reflects light in the visible region and transmits light in the infrared region, and a second surface that is formed on the opposite side of the first surface. It is desirable that the second surface is subjected to a surface treatment that increases light absorption efficiency. Since the second surface of the reflector is subjected to a surface treatment that increases the light absorption efficiency, the infrared light transmitted through the first surface can be absorbed by the second surface. Thereby, the heat generated by the light in the infrared region can be efficiently absorbed by the refrigerant in the heat-absorbing means for the light source.

  Moreover, as a preferable aspect of the present invention, it is desirable to further include a cooling fan that cools the radiator and the light source unit by flowing air from the radiator toward the light source unit. Since the radiator and the light source unit can be cooled by a single cooling fan, the projector can be downsized, the number of parts can be reduced, and the manufacturing cost can be reduced. In addition, quietness can be improved as compared with the case where a plurality of fans are provided. Even if air that has risen in temperature by absorbing heat from a radiator is allowed to flow toward the light source, the temperature of the light source is very high, so the temperature difference between the air and the light source can be increased. Cooling efficiency can be ensured.

  As a preferred embodiment of the present invention, it is desirable that the radiator and the evaporator are connected via a capillary tube. Since the radiator and the evaporator are connected via the capillary tube, an appropriate amount of refrigerant according to the pressure difference between the radiator and the evaporator is supplied into the evaporator. That is, there is no need to provide a valve or the like for adjusting the flow rate of the refrigerant between the radiator and the evaporator, and the number of parts can be reduced and the manufacturing cost can be reduced.

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

  FIG. 1 shows a schematic configuration of a projector according to Embodiment 1 of the present invention. The projector 1 is a front projection type projector that appreciates an image by supplying light to a screen (not shown) and observing the light reflected by the screen. The projector 1 cools the arc tube (light source unit) 4 and the spatial light modulator (optical element) 14 that are heat sources by the cooling system S1. The cooling system S1 includes a circulation pump 2, an absorption evaporator (light source heat absorption means) 5, an ejector pump 6, a radiator (heat radiator) 8, a cooling fan 10, a low-temperature heat exchanger (evaporator) 12, and a heat transfer means 16. And generally configured. The circulation pump 2, the absorption evaporator 5, the ejector pump 6, the radiator 8, and the low temperature heat exchanger 12 are connected via a refrigerant pipe 18.

  The circulation pump 2 functions as a power source for circulating the refrigerant between the absorption evaporator 5, the ejector pump 6, the radiator 8, and the low-temperature heat exchanger 12 connected to each other via the refrigerant pipe 18. As the refrigerant, for example, water, hydrofluoroether, fluorine-based inert liquid, propylene glycol, ethylene glycol, or the like is used.

  The arc tube 4 is, for example, an ultra high pressure mercury lamp. The arc tube 4 emits light by forming an arc between electrodes (not shown), and becomes extremely hot at 800 ° C. to 1000 ° C. during light emission.

  FIG. 2 is a cross-sectional view showing a schematic configuration of the absorption evaporator 5. The absorption evaporator 5 includes a reflector 20 and a heat absorption block 22. The surface (first surface 20a) of the reflector 20 with respect to the arc tube 4 is a cold mirror that reflects light in the visible region but transmits light in the infrared region and light in the ultraviolet region. The reflector 20 reflects light in the visible region of the light emitted from the arc tube 4 toward the spatial light modulator 14. The surface (second surface 20b) opposite to the first surface 20a of the reflector 20 is subjected to a surface treatment that enhances light absorption efficiency. For example, the second surface 20b is subjected to a surface treatment such that the emissivity is 0.8 or more, and most of the light in the infrared region transmitted through the first surface 20a is absorbed by the second surface 20b. Since the second surface 20b absorbs most of the light in the infrared region, the portion where the temperature rises due to the light in the infrared region transmitted through the first surface 20a can be limited to the second surface 20b portion.

  The heat absorption block 22 is disposed on the second surface 20 b side of the reflector 20. The heat absorption block 22 is a block material filled with a metal material having high thermal conductivity, for example, aluminum, and a flow path 22a through which a refrigerant passes is formed in a meandering shape in a three-dimensional shape. The heat absorption block 22 is provided in contact with the second surface 20 b of the reflector 20, and the heat generated on the second surface 20 b is transmitted to the heat absorption block 22. The heat transmitted to the endothermic block 22 is absorbed by the refrigerant passing through the flow path 22a in the endothermic block 22. Further, the temperature of the heat absorption block 22 is also increased by the arc tube 4 having a high temperature, and the heat is absorbed by the refrigerant. The heat absorption block 22 evaporates the refrigerant passing through the flow path 22a because the heat generated by the infrared light emitted from the arc tube 4 or the heat transmitted from the arc tube 4 itself becomes higher than the boiling temperature of the refrigerant. A gas phase refrigerant is used.

  The ejector pump 6 has a coaxial double nozzle shape in which the sub nozzle 6b surrounds the main nozzle 6a. In addition, a communication hole 6c that communicates the main nozzle 6a and the sub nozzle 6b is formed in the wall surface of the main nozzle 6a. The absorption evaporator 5 is connected to the main nozzle 6 a of the ejector pump 6 via the refrigerant pipe 18, and the refrigerant that has become a gas phase in the heat absorption block 22 flows into the main nozzle 6 a. A low temperature heat exchanger 12 is connected to the sub nozzle 6 b of the ejector pump 6 via a refrigerant pipe 18.

  When the refrigerant passes through the main nozzle 6a, the pressure in the sub nozzle 6b is reduced through the communication hole 6c. Thereby, the inside of the low-temperature heat exchanger 12 connected to the sub nozzle 6b is decompressed. That is, the ejector pump 6 functions as a decompression unit that decompresses the inside of the low-temperature heat exchanger 12. As will be described in detail later, a refrigerant is accommodated in the low-temperature heat exchanger 12. When the inside of the low-temperature heat exchanger 12 is depressurized by the ejector pump 6, the boiling temperature of the refrigerant is lowered and the refrigerant is easily evaporated. A vapor-phase refrigerant is generated by the evaporation of the refrigerant in the low-temperature heat exchanger 12, and the vapor-phase refrigerant takes heat of vaporization from the liquid-phase refrigerant when it evaporates. The gas-phase refrigerant generated in the low-temperature heat exchanger 12 is drawn into the main nozzle 6 a via the sub nozzle 6 b, merged with the gas-phase refrigerant sent from the absorption evaporator 5, and sent to the radiator 8. The ejector pump 6 has a higher pressure reducing effect on the sub nozzle 6b as the speed of the fluid passing through the main nozzle 6a increases. In the first embodiment, the refrigerant passing through the main nozzle 6a evaporates in the absorption evaporator 5 and becomes a gas-phase refrigerant, so that the refrigerant passes through the main nozzle 6a at a higher speed than the liquid-phase refrigerant. Can do. Therefore, the pressure reduction effect of the sub nozzle 6b can be enhanced, and the pressure inside the low temperature heat exchanger 12 can be made lower. Thereby, the evaporation temperature of the refrigerant inside the low-temperature heat exchanger 12 is further lowered.

  The radiator 8 radiates heat absorbed by the refrigerant in the absorption evaporator 5 and heat taken as vaporization heat in the low-temperature heat exchanger 12 to the outside air. A flow path (not shown) through which a refrigerant flows is formed inside the radiator 8. The gas-phase refrigerant sent from the ejector pump 6 is condensed in the process of flowing through the flow path in the radiator 8 to be condensed into a liquid-phase refrigerant. The refrigerant that has passed through the radiator 8 is directed to the absorption evaporator 5 via the circulation pump 2. Since the liquid phase refrigerant is less likely to decrease in volume when pumped than the gas phase refrigerant, the circulation pump 2 that pumps the liquid phase refrigerant can be smaller than the compressor that pumps the gas phase refrigerant.

  A refrigerant pipe 18 connecting the radiator 8 and the absorption evaporator 5 branches in the middle and is connected to the low temperature heat exchanger 12. Therefore, a part of the refrigerant flowing out of the radiator 8 is accommodated inside the refrigerant toward the low temperature heat exchanger 12.

  The cooling fan 10 increases the cooling efficiency of the refrigerant by causing the air around the radiator 8 to flow. A duct (air passage) 11 is provided around the cooling fan 10, and the air flowing by the cooling fan 10 is directed toward the arc tube 4. The air that has absorbed the heat of the refrigerant by the radiator 8 is flowed toward the arc tube 4 by the cooling fan 10 to cool the arc tube 4. Since the arc tube 4 has a very high temperature, the temperature difference from the arc tube 4 becomes large even if the temperature of the radiator 8 is increased by absorbing the heat of the refrigerant, so that the arc tube is sufficiently cooled. 4 cooling can be performed. In addition, since the radiator 8 and the arc tube 4 can be cooled by the single cooling fan 10, the projector 1 can be downsized and the parts can be reduced as compared with the case where fans for cooling the radiator 8 and the arc tube 4 are provided. This can contribute to a reduction in the number of points and a reduction in manufacturing costs. Moreover, quietness can be improved as compared with the case where a plurality of fans are provided. Note that cooling the radiator 8 and the arc tube 4 with separate fans is not excluded. Furthermore, the cooling fan 10 may also serve as another fan that is conventionally disposed in the projector, for example, a fan for cooling the power supply or a fan for discharging the air in the projector housing.

  The low-temperature heat exchanger 12 cools the refrigerant by evaporating the refrigerant accommodated therein. When the refrigerant evaporates inside the low-temperature heat exchanger 12, heat of vaporization is taken away and the refrigerant is cooled. Since the inside of the low-temperature heat exchanger 12 is depressurized by the ejector pump 6, the boiling temperature of the refrigerant decreases. Thereby, the temperature of the refrigerant accommodated in the low temperature heat exchanger 12 is cooled to a temperature near the boiling temperature. If the inside of the low-temperature heat exchanger 12 is depressurized so that the boiling temperature of the refrigerant is below room temperature, the refrigerant inside the low-temperature heat exchanger 12 can be cooled to below room temperature. A refrigerant pipe 18 connecting the radiator 8 and the low-temperature heat exchanger 12 is provided with a valve 13 for adjusting the flow rate of the refrigerant. By adjusting the flow rate of the refrigerant toward the low temperature heat exchanger 12 with the valve 13, it is possible to prevent the liquid phase refrigerant inside the low temperature heat exchanger 12 from being drawn into the ejector pump 6.

  The spatial light modulation device 14 is a transmissive liquid crystal display device that modulates light emitted from the arc tube 4 in accordance with an image signal. The light modulated by the spatial light modulator 14 is projected onto a screen (not shown) to display an image. The temperature of the spatial light modulator 14 increases due to irradiation of light emitted from the arc tube 4. The heat generated in the spatial light modulator 14 is transmitted through the heat transfer means 16 and is absorbed by the refrigerant in the low temperature heat exchanger 12.

  The heat transfer means 16 is made of a material having high thermal conductivity, for example, a metal material such as aluminum or copper. The heat transfer means 16 is provided in contact with both the spatial light modulator 14 and the liquid phase refrigerant inside the low-temperature heat exchanger 12. The heat generated in the spatial light modulator 14 is transmitted to the heat transfer means 16 and absorbed by the refrigerant inside the low-temperature heat exchanger 12, and the spatial light modulator 14 is cooled. Thereby, the deterioration of the spatial light modulator 14 due to the temperature rise can be prevented and the life of the projector 1 can be extended.

  Next, the flow of refrigerant circulation in the cooling system S1 will be described with reference to the flowchart of FIG.

  The refrigerant flows out of the radiator 8 and travels toward the absorption evaporator 5 (step S1). The refrigerant flowing out of the radiator 8 evaporates in the absorption evaporator 5 (step S2). When the refrigerant evaporated in the absorption evaporator 5 into the gas phase passes through the main nozzle 6a of the ejector pump 6 (step S3), the inside of the sub nozzle 6b is depressurized, whereby the inside of the low-temperature heat exchanger 12 is also depressurized. (Step S4). A part of the refrigerant flowing out of the radiator 8 is accommodated inside the low temperature heat exchanger 12, and a part of the accommodated refrigerant evaporates by reducing the pressure inside the low temperature heat exchanger 12. Is cooled (step S5). The refrigerant that has evaporated into the gas phase inside the low-temperature heat exchanger 12 is drawn into the sub nozzle 6b and merges with the refrigerant that passes through the main nozzle 6a (step S6). The refrigerant joined by the ejector pump 6 flows into the radiator 8 and is condensed by being absorbed by the outside air in the process of passing through the flow path in the radiator 8 (step S7). The refrigerant aggregated by the radiator 8 flows out again toward the evaporation absorber 5 (step S8).

  As described above, the projector 1 according to the present invention cools the spatial light modulation device 14 by causing the refrigerant cooled by the low-temperature heat exchanger 12 to absorb the heat generated by the spatial light modulation device 14 and thus cools the spatial light modulation. Deterioration of the device 14 can be prevented and the product life of the projector 1 can be extended. Further, since the refrigerant is evaporated using the heat of the arc tube 4 that becomes very high temperature, and the refrigerant that has become a gas phase by the evaporation is passed through the ejector pump 6, the inside of the low-temperature heat exchanger 12 is sufficiently decompressed. be able to. Since the inside of the low-temperature heat exchanger 12 is sufficiently depressurized, the evaporation temperature of the refrigerant accommodated therein can be lowered. If the evaporation temperature of the refrigerant is lowered, the refrigerant inside the low-temperature heat exchanger 12 can be sufficiently cooled even in an environment of about room temperature, and the temperature of the refrigerant can be reduced to room temperature or lower. Since the spatial light modulator 14 is cooled by the sufficiently cooled refrigerant, the cooling effect can be enhanced. Since the spatial light modulator 14 is cooled by absorbing heat in the refrigerant cooled by the low-temperature heat exchanger 12, the number of components can be reduced. Further, even when a fan for cooling the spatial light modulator 14 is provided, the spatial light modulator 14 can be cooled with a small air volume, so that the operation noise of the fan is suppressed and the silence of the projector 1 is suppressed. Can be improved.

  Steam that passes through the main nozzle 6a of the ejector pump 6 that depressurizes the inside of the low-temperature heat exchanger 12 is generated by the heat energy generated by the arc tube 4 that has been discarded in the past. Power consumption can be reduced compared to the case of using.

  Further, the ejector pump 6 can be easily miniaturized as compared with the compressor, and can contribute to the miniaturization of the cooling system S1 and the miniaturization of the projector 1.

  In the first embodiment, a transmissive liquid crystal display device is used as the spatial light modulator, but the present invention is not limited to this. As the spatial light modulator, a reflective liquid crystal display (Liquid Crystal On Silicon; LCOS), DMD (Digital Micromirror Device), GLV (Grating Light Valve), or the like may be used. When a reflective liquid crystal display device is used as the spatial light modulator, the heat transfer means 16 is brought into contact with the back side of the reflective surface of the reflective liquid crystal display device so as to dissipate heat generated by the reflective liquid crystal display device. You may comprise. In addition, although the spatial light modulator 14 is the object to be cooled by the refrigerant cooled by the low-temperature heat exchanger 12, other heat sources such as a polarizing plate and an electric circuit provided in the projector 1 may be the object to be cooled.

  In the first embodiment, the refrigerant evaporated by the absorption evaporator 5 as the heat absorbing means for the light source is used in the main nozzle 6a of the ejector pump 6. However, the present invention is not limited to this. The sub-nozzle 6b can also be depressurized by passing it through the main nozzle 6a of the ejector pump 6 in the liquid phase without evaporating the refrigerant with the light-absorbing means.

  FIG. 4 shows a schematic configuration of the projector 1 according to the first modification of the first embodiment. The same parts as those in the above-described configuration are denoted by the same reference numerals, and redundant description is omitted.

  The cooling system S <b> 1 included in the projector 1 according to the first modification includes a capillary tube 24 between the radiator 8 and the low temperature heat exchanger 12. The inside of the capillary tube 24 is a capillary tube, and an amount of the refrigerant according to the pressure difference between the refrigerant inflow side and the outflow side with respect to the capillary tube 24 passes. Therefore, an appropriate amount of refrigerant can be allowed to flow into the low-temperature heat exchanger 12 without providing the valve 13 for adjusting the flow rate of the refrigerant between the radiator 8 and the low-temperature heat exchanger 12. Since the valve 13 is unnecessary, it is possible to contribute to the reduction of the number of parts and the miniaturization of the projector 1.

  FIG. 5 shows a schematic configuration of the projector 1 according to the second modification of the first embodiment. FIG. 6 is a cross-sectional view of the low-temperature heat exchanger 12 and the spatial light modulator 14 as seen from the arc tube 4 side. The same parts as those in the above-described configuration are denoted by the same reference numerals, and redundant description is omitted.

  In the cooling system S1 included in the projector 1 according to the second modification, the low-temperature heat exchanger 12 is configured so as to surround the spatial light modulator 14. The spatial light modulator 14 is in contact with the low-temperature heat exchanger 12 at the periphery thereof. With this configuration, the heat generated in the spatial light modulator 14 can be directly absorbed by the refrigerant in the low-temperature heat exchanger 12, so that the efficiency is high. In addition, since the low-temperature heat exchanger 12 functions as an optical element heat absorption unit, the configuration requirements of the heat transfer unit 16 and the like are not required, which can contribute to a reduction in the number of components and a reduction in the size of the projector 1.

  FIG. 7 shows a schematic configuration of the projector 51 according to the second embodiment of the invention. The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The cooling system S2 included in the projector 51 according to the second embodiment cools the spatial light modulator 14 using the heat pipe 30 surrounding the spatial light modulator 14, and a part thereof is inside the evaporator. A part of the heat pipe 30 is brought into contact with the arranged piping system (heat pipe circulation system), and the heat from the spatial light modulator 14 is absorbed by the refrigerant in the heat pipe circulation system to be cooled. Features.

FIG. 8 is a front view of the spatial light modulator 14 and the heat pipe (optical element heat absorbing means) 30 as viewed from the arc tube 4 side. The heat pipe 30 surrounds the spatial light modulation device 14 and is disposed in contact with the spatial light modulation device 14. The heat pipe 30 is made of a material having high thermal conductivity, for example, a metal material such as aluminum or copper. A heat pipe circulation system is configured including the heat pipe 30 and a heat pipe refrigerant pipe (pipe) 26 connected to the heat pipe 30 for circulating the refrigerant. The heat pipe circulation system is a separate pipe from the system in which the evaporator 12 and the like are incorporated, and the refrigerant separated from the refrigerant in the evaporator 12 flows through the heat pipe circulation system. Further, a heat pipe circulation pump 28 is provided in the middle of the heat pipe refrigerant pipe 26 as a power source for circulating the refrigerant.

Heat generated by the temperature rise of the spatial light modulator 14 is absorbed by the refrigerant flowing through the heat pipe refrigerant pipe 26 via the heat pipe 30. Therefore, the spatial light modulator 14 is uniformly cooled from its surroundings by the heat pipe 30. Since the spatial light modulator 14 is uniformly cooled from the surroundings, the temperature distribution of the spatial light modulator 14 can be eliminated and stable light modulation can be achieved. Further, the lifetime of the projector 51 can be extended by preventing the spatial light modulator 14 from being deteriorated due to a temperature rise.

  A part of the heat pipe refrigerant pipe 26 is disposed inside the low-temperature heat exchanger 12. The heat from the spatial light modulator 14 absorbed by the heat pipe 30 is absorbed by the refrigerant cooled in the low temperature heat exchanger 12 in the process of passing through the low temperature heat exchanger 12. Then, the heat pipe 30 again absorbs heat from the spatial light modulator 14.

Since only the liquid-phase refrigerant flows in the heat pipe circulation system, the refrigerant in the pipe is difficult to dissipate outside the pipe. Therefore, at least a part of the heat pipe refrigerant pipe 26 is a flexible rubber tube 31. Thereby, when moving the heat pipe 30 and the spatial light modulator 14, it is not necessary to move the absorption evaporator 5, the low temperature heat exchanger 12, and the like. In the manufacturing process of the projector 51, fine adjustment of the arrangement position of the spatial light modulation device 14 may be necessary. Can be done. In addition to the rubber tube 31, a metal pipe or the like formed in a bellows shape may be used as the flexible tube.

  In the second embodiment, the refrigerant flowing in the flow path 30a of the heat pipe 30 is independent as a heat pipe circulation system. However, the present invention is not limited to this, and the heat pipe 30 and the low-temperature heat exchanger 12 are connected. The heat pipe 30 may be directly cooled by the low-temperature heat exchanger 12 by contact fixing.

  FIG. 9 shows a schematic configuration of the projector 101 according to the third embodiment of the invention. The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The arc tube 4 is a light source unit that emits light including red (R) light, green (G) light, and blue (B) light, and is, for example, an ultra-high pressure mercury lamp.

  The first integrator lens 112 and the second integrator lens 113 have a plurality of lens elements arranged in an array. The first integrator lens 112 divides the light flux from the arc tube 4 into a plurality of parts. Each lens element of the first integrator lens 112 condenses the light beam from the arc tube 4 in the vicinity of the lens element of the second integrator lens 113. The lens element of the second integrator lens 113 forms an image of the lens element of the first integrator lens 112 on the spatial light modulator.

  Light that has passed through the two integrator lenses 112 and 113 is converted into linearly polarized light in a specific vibration direction by the polarization conversion element 114. The superimposing lens 115 superimposes the image of each lens element of the first integrator lens 112 on the spatial light modulator. The first integrator lens 112, the second integrator lens 113, and the superimposing lens 115 make the intensity distribution of light from the arc tube 4 uniform on the spatial light modulator. Light from the superimposing lens 115 enters the first dichroic mirror 116. The first dichroic mirror 116 reflects R light and transmits G light and B light. The R light reflected by the first dichroic mirror 116 has its optical path bent by the first dichroic mirror 116 and the reflection mirror 117, and enters the R light field lens 118R. The R light field lens 118R collimates the R light from the reflection mirror 117 and makes it incident on the R light spatial light modulator 14R.

  The spatial light modulator 14R for R light is a spatial light modulator that modulates R light according to an image signal. The R light modulated by the R light spatial light modulator 14R is incident on the cross dichroic prism 120 which is a color synthesis optical system.

  The G light and B light transmitted through the first dichroic mirror 116 enter the second dichroic mirror 121. The second dichroic mirror 121 reflects G light and transmits B light. The G light reflected by the second dichroic mirror 121 has its optical path bent by the second dichroic mirror 121 and enters the G light field lens 118G. The G light field lens 118G collimates the G light from the second dichroic mirror 121 and makes it incident on the G light spatial light modulator 14G. The spatial light modulation device 14G for G light is a spatial light modulation device that modulates G light according to an image signal. The G light modulated by the G light spatial light modulator 14G is incident on a different surface of the cross dichroic prism 120 from the surface on which the R light is incident.

  The B light transmitted through the second dichroic mirror 121 is transmitted through the relay lens 122, and then the optical path is bent by reflection at the reflection mirror 123. The B light from the reflection mirror 123 further passes through the relay lens 124, and then the optical path is bent by the reflection by the reflection mirror 125, and enters the B light field lens 118B. Since the optical path of the B light is longer than the optical path of the R light and the optical path of the G light, relay lenses 122 and 124 are provided in the optical path of the B light in order to make the illumination magnification in the spatial light modulator equal to that of other color lights. The relay optical system to be used is adopted.

  The B light field lens 118B collimates the B light from the reflection mirror 125 and makes it incident on the B light spatial light modulator 14B. The B light spatial light modulation device 14B is a spatial light modulation device that modulates B light according to an image signal. The B light modulated by the B light spatial light modulator 14B is incident on a surface of the cross dichroic prism 120 different from the surface on which the R light is incident and the surface on which the G light is incident.

  The cross dichroic prism 120 has two dichroic films 126 and 127 arranged so as to be substantially orthogonal to each other. The first dichroic film 126 reflects R light and transmits G light and B light. The second dichroic film 127 reflects B light and transmits R light and G light. The cross dichroic prism 120 combines R light, G light, and B light incident from different directions, and emits the light toward the projection lens 128. The projection lens 128 projects the light combined by the cross dichroic prism 120 in the direction of the screen 129 and displays an image on the screen 129.

  The arc tube 4, the R light spatial light modulation device 14R, the G light spatial light modulation device 14G, and the B light spatial light modulation device 14B, which are heat sources in the projector 101 according to the third embodiment, are described in the first embodiment. Cool using a cooling system. This prevents the deterioration of the R light spatial light modulation device 14R, the G light spatial light modulation device 14G, and the B light spatial light modulation device 14B, thereby extending the product life of the projector 101.

  The projector 101 is not limited to the configuration including the spatial light modulation device for each color light, and may be configured to modulate two or three or more color lights by one spatial light modulation device. The projector 101 may be a so-called rear projector that supplies light to one surface of the screen and observes an image by observing light emitted from the other surface of the screen.

1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment of the invention. Sectional drawing which shows schematic structure of an absorption evaporator. The flowchart for demonstrating the flow of a circulation of a refrigerant | coolant. FIG. 6 is a diagram illustrating a schematic configuration of a projector according to a first modification of the first embodiment. FIG. 6 is a diagram illustrating a schematic configuration of a projector according to a second modification of the first embodiment. Sectional drawing which looked at the low-temperature heat exchanger and the spatial light modulator from the arc tube side. FIG. 5 is a diagram illustrating a schematic configuration of a projector according to a second embodiment of the invention. The figure which looked at the spatial light modulation device and the heat pipe from the arc tube side. FIG. 6 is a diagram illustrating a schematic configuration of a projector according to a third embodiment of the invention.

Explanation of symbols

S1, S2 cooling system, 1, 51, 101 projector, 2 circulation pump, 4 arc tube (light source part), 5 absorption evaporator (light absorption means for light source), 6 ejector pump, 6a main nozzle, 6b sub nozzle, 6c communication Hole, 8 Radiator (radiator), 10 Cooling fan, 11 Duct (air path), 12 Low-temperature heat exchanger (evaporator), 13 Valve, 14 Spatial light modulator (optical element), Spatial light modulation for 14R light Device, spatial light modulation device for 14G G light, spatial light modulation device for 14B B light, 16 heat transfer means (heat absorption means for optical element), 18 refrigerant pipe, 20 reflector, 20a first surface, 20b second surface, 22 Heat absorption block, 22a flow path, 24 capillary tube, 26 heat pipe refrigerant pipe (pipe), 28 heat pipe circulation pump, 30 heat pipe, 30a flow path, 31 rubber tube, 112 first integrator lens, 113 second integrator lens, 114 polarization conversion element, 115 superimposing lens, 116 first dichroic mirror, 117, 123, 125 reflection mirror, 118RR field lens for R light, 118G G light field lens, 118B B light field lens, 120 cross dichroic prism, 121 second dichroic mirror, 122, 124 relay lens, 126, 127 dichroic film, 128 projection lens, 129 screen

Claims (11)

A projector having a light source unit that emits light and displaying an image using light emitted from the light source unit,
A light-absorbing means for the light source that causes the refrigerant to absorb heat from the light source unit;
An ejector pump that passes the refrigerant that has absorbed heat by the heat absorbing means for the light source;
A radiator that dissipates the heat of the refrigerant that has flowed out of the ejector pump;
An evaporator that evaporates and cools the stored refrigerant, and
Heat absorbed from a heat source other than the light source is absorbed by the refrigerant cooled by the evaporator,
The projector according to claim 1, wherein the ejector pump decompresses the interior of the evaporator by a pressure drop caused by the passage of the refrigerant that has absorbed heat by the light-absorbing means for light source.   The projector according to claim 1, wherein the heat absorbing means for the light source evaporates the refrigerant.   The projector according to claim 1, wherein the heat source is an optical element that modulates light emitted from the light source unit.   The projector according to claim 3, further comprising a heat pipe surrounding the periphery of the optical element, wherein a part of the heat pipe is fixed to the evaporator to exchange heat.   The projector according to claim 3, wherein the optical element is disposed in contact with the evaporator. A heat absorbing means for an optical element that absorbs heat from the optical element in a refrigerant separated from the refrigerant in the evaporator and flowing;
The projector according to claim 3, further comprising: a pipe disposed inside the evaporator and configured to pass a refrigerant that has absorbed heat by the heat absorbing means for the optical element.   The projector according to claim 6, wherein the heat absorbing means for the optical element and the pipe are connected by a flexible tube. The optical element heat absorbing means includes a heat pipe surrounding the optical element,
The projector according to claim 6 or 7, wherein a part of the heat pipe is cooled by a refrigerant that flows separately from the refrigerant in the evaporator. The light source heat absorbing means includes a reflector having a first surface that reflects light in the visible region and transmits light in the infrared region, and a second surface formed on the opposite side of the first surface,
The projector according to any one of claims 1 to 8, wherein the second surface is subjected to a surface treatment that increases light absorption efficiency.   10. The cooling fan according to claim 1, further comprising a cooling fan that cools the radiator and the light source unit by causing air to flow from the radiator toward the light source unit. 11. The projector described.   The projector according to any one of claims 1 to 10, wherein the radiator and the evaporator are connected via a capillary tube.

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