JP2010249945A - Cooling system and projection type video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system capable of stably outputting large power by using a thermoelectric transducer. <P>SOLUTION: The cooling system includes: a heat sink 41 in which a coolant in a mixed fluid state is produced by heat from a light source device 21; a storage chamber 42 in which liquid coolant and vapor are stored; a first transport path 45 which connects the heat sink 41 and the storage chamber 42; a heat radiation unit 44 which allows the liquid coolant flowing out from the storage chamber 42 to radiate heat; a heat exchanger 43 which subjects the liquid coolant flowing out from the heat radiation unit 44 to heat exchange between the liquid coolant and the vapor in the storage chamber 42; and a third transport path 47 which connects the heat radiation unit 44 and the heat exchanger 43. The first transport path 45 and the third transport path 47 are partially, at least, made proximate to each other, and the thermoelectric transducer 49 which generates electric power according to a temperature difference between the first transport path 45 and the third transport path 47 is arranged in the proximate portion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cooling system for cooling an object to be cooled and a projection display apparatus equipped with the cooling system.

  Conventionally, a pumpless cooling system that circulates refrigerant without using a pump is known (Patent Document 1). In this cooling system, the refrigerant is circulated by utilizing the buoyancy of vapor generated by the boiling of the liquid refrigerant. Thus, heat transport from the heat absorber (heating heat exchanger) to the heat radiator (sensible heat release heat exchanger) is realized without using a pump.

  In this cooling system, a cooling fan may be used to forcibly cool the liquid refrigerant flowing through the radiator. In this case, in order to further reduce the power consumption of the cooling system, it is desirable to suppress external power required for driving the cooling fan as much as possible. In addition, when this cooling system is mounted on an electric device such as a projector, it is desirable to save power of the entire device.

  Note that a power generation apparatus that generates power by attaching a thermoelectric conversion element to a lamp is known (Patent Document 2). In this power generation device, power generation is performed by a temperature difference generated between the upper substrate heated by the heat generated by the lamp and the lower substrate not heated. Here, a plurality of heat dissipation pins are provided on the lower substrate in order to improve heat dissipation.

JP 2005-195226 A JP 2004-296879 A

  The thermoelectric conversion element outputs larger electric power as a larger temperature difference is given. Therefore, when applying a thermoelectric conversion element to the said cooling system, it becomes a subject to give a big temperature difference to a thermoelectric conversion element stably.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a cooling system capable of stably generating a large amount of electric power using a thermoelectric conversion element, and a projection type image display apparatus equipped with the cooling system. And

  The first aspect of the present invention includes a heat absorption part that absorbs heat from an object to be cooled and changes the state of the refrigerant to a mixed fluid of liquid and gas, a heat dissipation part that releases heat from the liquid refrigerant, and the heat absorption part. The present invention relates to a cooling system including a heat exchanging unit that is arranged above the unit and that performs heat exchange between the refrigerant of the mixed fluid generated by the heat absorbing unit and the liquid refrigerant radiated by the heat radiating unit. In the cooling system of this aspect, at least a part of the high temperature side transportation path connecting the heat absorption section and the heat exchange section and the low temperature side transportation path connecting the heat radiation section and the heat exchange section are arranged close to each other. Is done. Furthermore, the thermoelectric conversion element which is distribute | arranged between the said adjacent part of the said high temperature side transport path and the said low temperature side transport path, and produces electric power by the temperature difference of the said high temperature side transport path and the said low temperature side transport path is provided.

  According to the cooling system according to the first aspect, since the thermoelectric conversion element can be arranged between the high temperature side transportation path that is in the highest temperature state and the low temperature side transportation path that is in the lowest temperature state, the thermoelectric conversion element A large temperature difference can be stably provided. Therefore, large electric power can be stably output from the thermoelectric conversion element.

  The cooling system according to the first aspect may be configured to include a cooling fan that is disposed in the heat radiating unit and is driven by electric power from the thermoelectric conversion element.

  In this way, it is possible to reduce the external power used for driving the cooling fan.

  The cooling system which concerns on a 1st aspect may be comprised so that the heat insulation member for suppressing the heat transfer in the said adjacent part of the said high temperature side transport path and the said low temperature side transport path may be arrange | positioned.

  If it does in this way, the heat transfer between the high temperature side transport path and the low temperature side transport path in the part where the thermoelectric conversion element is not arranged can be prevented. As a result, the amount of steam generated decreases due to a decrease in the temperature of the high temperature side transportation path, or the temperature difference between the high temperature side transportation path and the low temperature side transportation path decreases, resulting in a decrease in the power generation amount of the thermoelectric conversion element Can be prevented.

  A second aspect of the present invention relates to a projection display apparatus. The projection display apparatus according to this aspect includes the cooling system according to the first aspect.

  According to the projection display apparatus according to the second aspect, similarly to the first aspect, a large temperature difference can be stably given to the thermoelectric conversion element.

  Here, the object to be cooled that is cooled by the cooling system is, for example, a light source. In this case, the light source may be configured to include a reflector that reflects visible light and transmits other light. At this time, a black layer is formed on the surface that contacts the reflector in the heat absorbing portion.

  If it does in this way, light other than visible light from a light source can be effectively passed to a heat absorption part as heat.

  As described above, according to the present invention, it is possible to provide a cooling system and a projection display apparatus that can stably generate a large amount of electric power using a thermoelectric conversion element.

  The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely an example when the present invention is implemented, and the present invention is not limited to what is described in the following embodiment.

It is an internal perspective view which shows the structure of the projector which concerns on embodiment. It is the perspective view and internal perspective view which show the structure of the cooling unit which concerns on embodiment. It is sectional drawing which shows the attachment structure of the light source device to the heat absorber which concerns on embodiment. It is sectional drawing which shows the structure of the thermoelectric conversion element which concerns on embodiment, and an internal perspective figure which shows the structure of a jacket part. It is a circuit block diagram which shows the drive unit of the cooling fan which concerns on embodiment. It is a flowchart of the drive control by the drive unit which concerns on embodiment.

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

  FIG. 1 shows a configuration of a projector according to the present embodiment. This figure is an internal perspective view when the projector is viewed from above.

  The projector includes a housing 10, an optical engine 20, a lens unit 30, and a cooling unit 40.

  An optical engine 20 is accommodated in the housing 10, and the optical engine 20 generates light modulated in accordance with a video signal (hereinafter referred to as “video light”).

  The optical engine 20 includes a light source device 21, a light guide optical system 22, three transmissive liquid crystal panels 23, 24, and 25, and a dichroic prism 26.

  The light source device 21 is a lamp light source and emits white light. The configuration of the light source device 21 will be described in detail later.

  The white light emitted from the light source device 21 is transmitted through the light guide optical system 22 to light in the red wavelength band (hereinafter referred to as “R light”), light in the green wavelength band (hereinafter referred to as “G light”), and blue light. The light is separated into light of a wavelength band (hereinafter referred to as “B light”) and irradiated to the liquid crystal panels 23, 24, and 25. Note that polarizing plates (not shown) are arranged before and after each of the liquid crystal panels 23, 24, and 25. The R light, G light, and B light modulated by the liquid crystal panels 23, 24, and 25 are color-synthesized by the dichroic prism 26 and emitted as video light.

  A lens unit 30 is attached to the optical engine 20, and a front portion of the lens unit 30 is exposed from the front surface of the housing 10. The image light generated by the optical engine 20 is projected by the lens unit 30 onto a screen surface arranged in front of the projector.

  As a display element disposed in the optical engine 20, a reflective liquid crystal panel or a MEMS device can be used in addition to the transmissive liquid crystal panels 23, 24, and 25. Further, when a liquid crystal panel or a MEMS device is used, for example, a single plate type optical system using a color wheel can be used instead of the three plate type as described above.

  The light source device 21 generates a large amount of heat when turned on. Therefore, in order to cool the light source device 21, a cooling unit 40 is disposed in the housing 10.

  FIG. 2 shows the configuration of the cooling unit 40. FIG. 2A is a perspective view of the cooling unit 40, and FIG. 2B is an internal perspective view of the cooling unit 40 as viewed from the front side of the light source device 21.

  The cooling unit 40 includes a heat absorber 41, a storage chamber 42, a heat exchanger 43, and a heat dissipation unit 44.

  The heat absorber 41 is formed with a housing recess 411 serving as a heat receiving portion. The light source device 21 is housed in the housing recess 411.

  FIG. 3 shows an attachment structure of the light source device 21 to the heat absorber 41. This figure is a cross-sectional view of a state in which the light source device 21 is mounted on the heat absorber 41.

  The light source device 21 includes a light emitting unit 211, a parabolic reflector 212 that surrounds the light emitting unit 211, and a cover 213 that covers the front opening of the reflector 212.

  The light emitting unit 211 is, for example, a xenon lamp. The reflector 212 is formed of wavelength-selective glass that reflects only visible light and transmits light other than visible light. The cover 213 is made of wavelength-selective glass that transmits only visible light and reflects light other than visible light.

  Of the light emitted from the light emitting unit 211, visible light (white light) is reflected directly or after being reflected by the reflector 212, and then travels forward through the cover 213. On the other hand, light other than visible light passes through the reflector 212.

  The outer peripheral surface of the reflector 212 is in contact with the surface of the housing recess 411. A black coating 412 is applied to the surface of the housing recess 411, and light other than visible light transmitted through the reflector 212 is effectively absorbed by the surface of the housing recess 411 and converted into heat. In addition, it can replace with the black coating 412 and can arrange | position a black heat conductive sheet on the surface of the accommodation recessed part 411. FIG.

  A liquid refrigerant is accommodated in the heat absorber 41, and the heat converted from light on the surface of the accommodating recess 411, that is, the heat emitted from the light source device 21 is the low-temperature liquid in the heat absorber 41. Heat exchange with refrigerant. Thereby, the light source device 21 is cooled. On the other hand, the liquid refrigerant is heated to boil, and a mixed fluid refrigerant of a high-temperature liquid refrigerant and vapor bubbles (hereinafter referred to as vapor bubbles) is generated in the heat absorber 41.

  Note that the refrigerant used in the cooling unit has a characteristic of boiling from a liquid state by heat exchange with the light source device 21. For example, distilled water or alcohol is used as the refrigerant.

  Returning to FIG. 2, a storage chamber 42 is disposed above the heat absorber 41. The outlet of the heat absorber 41 and the inlet of the storage chamber 42 are connected by a first transport path 45. The refrigerant of the mixed fluid flows into the storage chamber 42 from the heat absorber 41. In the storage chamber 42, the refrigerant of the mixed fluid is separated, the high-temperature liquid refrigerant is accumulated in the lower part, and the vapor is accumulated in the upper part.

  A heat exchanger 43 is disposed in the accommodation chamber 42. As shown in FIG. 2B, the heat exchanger 43 includes a distribution unit 431 that distributes the flowing liquid refrigerant, a plurality of pipe units 432 through which the liquid refrigerant distributed by the distribution unit 431 flows, It is comprised with the confluence | merging part 433 where the refrigerant | coolant of the liquid which has flowed through the pipe part 432 merges. The heat exchanger 43 is formed of a material having good thermal conductivity such as copper, and penetrates the containing chamber 42 in a state where the inlet and the outlet face in the lateral direction, that is, in a state where the longitudinal direction thereof faces in the lateral direction. .

  Thus, since the heat exchanger 43 is arranged in such a state that the dimensions are increased in the lateral direction, the housing chamber 42 can be thinned in the vertical direction, and even in a projector in which the height dimension cannot be increased so much, the heat absorption is also achieved. The container 41 and the storage chamber 42 can be appropriately arranged in the vertical direction.

  The heat radiating unit 44 includes a radiator 441 and a cooling fan 442 for air-cooling the radiator 441. The cooling fan 442 includes a fan 442a and a motor 442b that rotationally drives the fan.

  The outlet of the storage chamber 42 is connected to the inlet of the radiator 441 through the second transport path 46. The outlet of the radiator 441 is connected to the distribution unit 431 of the heat exchanger 43 via the third transport path 47. The radiator 441 cools the high-temperature liquid refrigerant flowing from the storage chamber 42 to about the environmental temperature by exchanging heat with the cooling air sent from the cooling fan 442.

  The liquid refrigerant cooled by the radiator 441 flows into the heat exchanger 43, and is heat-exchanged with the liquid refrigerant and vapor in the storage chamber 42 while flowing through the pipe portion 432, and is preheated. The heat exchange at this time causes the vapor to condense in the storage chamber 42, returns to the liquid refrigerant, and accumulates in the lower portion of the storage chamber 42.

  The junction 433 of the heat exchanger 43 is connected to the inlet of the heat absorber 41 by the fourth transport path 48, and the liquid refrigerant that has been heated by the heat exchanger 43 flows into the heat absorber 41. Thus, the liquid refrigerant is heated again in the heat absorber 41 to become a refrigerant of the mixed fluid.

  Vapor bubbles generated in the heat absorber 41 rise along the first transport path 45 toward the accommodation chamber 42 by buoyancy. At this time, the vapor bubbles raise the surrounding liquid refrigerant together. A liquid refrigerant circulates in the cooling unit 40 by a so-called bubble pump effect caused by such vapor bubbles.

  Thereby, in the cooling unit 40, heat transport can be performed between the heat absorber 41 and the heat radiating unit 44 without using a pump for circulating the liquid refrigerant.

  Thus, since the cooling unit 40 does not require a pump, the external power required for it is not necessary. However, electric power for driving the cooling fan 442 is still required. Therefore, if the external power required for the cooling fan 442 can be greatly reduced, the cooling unit 40 with very low power consumption can be realized.

  Therefore, the first transport path 45 and the third transport path 47 are arranged so that these partial sections are close to each other, and the thermoelectric conversion element 49 is disposed between the close portions. The thermoelectric conversion element 49 generates power due to the temperature difference between the first transport path 45 and the third transport path 47. The power obtained by the power generation is used as power for driving the motor 442b of the cooling fan 442.

  The first transport path 45 becomes the highest temperature in the cooling unit 40 when a refrigerant of a high-temperature mixed fluid generated by being heated by the heat absorber 41 flows. On the other hand, the third transport path 47 has the lowest temperature in the cooling unit 40 when the low-temperature liquid refrigerant cooled by the heat radiating unit 44 flows. Therefore, by arranging the thermoelectric conversion element 49 between them, a large temperature difference is stably given to the thermoelectric conversion element 49.

  The first transport path 45 includes a transport pipe 451, and a jacket portion 452 is disposed in the middle of the transport pipe 451. The third transport path 47 includes a transport pipe 471, and a jacket portion 472 is disposed in the middle of the transport pipe 471. The thermoelectric conversion element 49 has two substrates (described later) attached to these jacket portions 452 and 472.

  In addition, although the upstream part of the jacket parts 452 and 472 in the transport pipes 451 and 471 are also close to each other, thermal insulation members 453 and 473 are wound around these parts, respectively. Heat transfer is prevented.

  Thereby, it is possible to prevent the temperature difference from being reduced due to the movement of heat between the two jacket portions 451 and 472, and it is possible to prevent the power generation amount of the thermoelectric conversion element 49 from being reduced. Moreover, it can prevent that the temperature of the refrigerant | coolant of the mixed fluid which flows through the 1st transport path 45 falls, and the generation amount of a vapor bubble falls, and it can prevent that the circulation capability of a liquid refrigerant | coolant falls.

  In view of preventing the generation amount of steam bubbles from decreasing, it is desirable to wind a heat insulating member around the downstream portions of the jacket portions 452 and 472 in the transport pipes 451 and 471 adjacent to each other.

  FIG. 4 shows a configuration of the thermoelectric conversion element 49 and the jacket portions 452 and 472. 4A is a cross-sectional view of the thermoelectric conversion element 49 and the jacket portions 452 and 472, and FIG. 4B is an internal perspective view when the jacket portion is viewed from the front (mounting surface side).

  The thermoelectric conversion element 49 includes a high temperature side substrate 491 and a low temperature side substrate 492. These substrates 491 and 492 have a rectangular shape and are formed of an insulating ceramic material such as alumina.

  Between the high temperature side substrate 491 and the low temperature side substrate 492, a plurality of semiconductor elements each having a pair of a P-type semiconductor element 493 and an N-type semiconductor element 494 are arranged vertically and horizontally. The P-type semiconductor element 493 and the N-type semiconductor element 494 are electrically connected by an electrode plate 495. A lead wire (not shown) is connected to a predetermined position of the electrode plate 495.

  In the thermoelectric conversion element 49, the high temperature side substrate 491 is attached to the attachment surface of the jacket portion 452, and the low temperature side substrate 492 is attached to the attachment surface of the jacket portion 472.

  Jacket portions 452 and 472 are formed of a material having excellent thermal conductivity such as copper. The jacket portions 452 and 472 include jacket main bodies 452a and 472a. Channels 452b and 472b are formed in the jacket main bodies 452a and 472a. In the flow paths 452b and 472b, a plurality of straight fins 452c and 472c are formed to protrude from the wall surface on the mounting surface side at a predetermined interval. These straight fins 452c and 472c extend in the flow direction of the liquid refrigerant in the flow paths 452b and 472b. Inlet portions 452d and 472d and outlet portions 452e and 472e connected to the flow paths 452b and 472c are formed in the upper and lower portions of the jacket main bodies 452a and 472a, respectively.

  A high-temperature mixed fluid refrigerant flows through the jacket portion 452. At this time, the heat of the refrigerant of the mixed fluid is transmitted to the high temperature side substrate 491 of the thermoelectric conversion element 49 through the straight fins 452c and the wall surface. Thereby, the high temperature side board | substrate 491 becomes high temperature. On the other hand, the liquid refrigerant cooled to the low temperature by the heat radiating unit 44 flows through the jacket portion 472. At this time, the heat of the liquid refrigerant is transmitted to the low temperature side substrate 492 of the thermoelectric conversion element 49 through the straight fins 472c and the wall surface. Thereby, the low temperature side substrate 492 becomes low temperature.

  Thus, when a large temperature difference occurs between both ends of the P-type semiconductor element 493 and the N-type semiconductor element 494, an electromotive force is generated due to the Seepeck effect. The generated electric power is taken out from the lead wire through the electrode plate 495.

  The thermoelectric conversion element 49 is output as the size (area) of the high temperature side substrate 491 and the low temperature substrate 492 increases, and as the number of the pair of semiconductor elements arranged therebetween increases, that is, as the body size increases. The amount of power that is generated becomes large.

  In this projector, for example, when a xenon lamp is used as the light emitting unit 211 of the light source device 21, when the light emission efficiency of the light source device 21 is 50 lm / W and the light emission spectrum is approximated as flat, the input power to the light source device 21 is About 73% of this can be heat. Therefore, for example, if the light source device 21 with an output of 2000 W is used, about 1460 W of heat is discharged from the light source device 21. Thereby, for example, when the cooling unit 40 is configured to have a thermal resistance value of 0.1 ° C./W, the temperature rise of the liquid refrigerant in the heat absorber 41 is about 146 ° C. The temperature of the light source device 21 rises only to about 186 ° C. even in a state where the environmental temperature is 40 ° C., and is maintained below the quality assurance temperature (400 to 500 ° C.).

  In this case, since the performance (air flow) of the cooling fan 442 is set so that the temperature of the liquid refrigerant that has become high as the temperature rises by about 146 ° C. can be reduced by the heat dissipation unit 44, the thermoelectric conversion element 49 is The main body size is set according to the power consumption of the cooling fan 442 at this time.

  FIG. 5 shows a configuration of the drive unit 50 for driving the cooling fan 442 by the electric power from the thermoelectric conversion element 49.

  The drive unit 50 includes a storage battery 501, a switching element 502, a voltage detection circuit 503, and a control circuit 504.

  The storage battery 501 stores the power supplied from the thermoelectric conversion element 49. The switching element 502 selectively supplies power from the storage battery 501 and power from an external power source to the cooling fan 442.

  The voltage detection circuit 503 detects the voltage of the storage battery 501 and outputs it to the control circuit 504. The control circuit 504 performs switching control of the switching element 502 based on the voltage detected by the voltage detection circuit 503. The control circuit 504 includes a timer 505.

  FIG. 6 is a processing flow of drive control of the cooling fan 442 by the control circuit 504. Hereinafter, the drive control of the cooling fan 442 will be described with reference to FIG.

  When the projector is stopped, the temperature of the liquid refrigerant in the cooling unit 40 is substantially constant, and the temperature difference between the jacket part 451 of the first transport path 45 and the jacket part 472 of the second transport path 47 is almost zero. Absent.

  When the operation of the projector is started and the light emitting unit 211 is turned on along with this, the liquid refrigerant in the heat absorber 41 is heated. Thereafter, when the liquid refrigerant begins to boil, the liquid refrigerant begins to circulate in the cooling unit 40 by the bubble bubble action of the vapor bubbles described above.

  When the light emitting unit 211 is turned on (S101: YES), the control circuit 504 determines whether or not the detection voltage of the voltage detection circuit 503 exceeds a specified value (S102). The specified value is a voltage value that can drive the cooling fan 442 appropriately.

  Since the liquid refrigerant does not circulate sufficiently for a while after the light emitting unit 211 is turned on, the temperature difference between the jacket part 452 and the jacket part 472 becomes small. For this reason, since the thermoelectric conversion element 49 does not generate sufficient power, the detected voltage becomes smaller than the specified value.

  When the control circuit 504 determines that the detected voltage is less than the specified value (S102: NO), the switching element 502 that has been in the off state is switched to the external power supply side, and power is supplied from the external power supply to drive the cooling fan 442. (S103). Thereby, the cooling fan 442 can be driven even when the power generation amount of the thermoelectric conversion element 49 is not sufficient.

  After that, when the liquid refrigerant circulates sufficiently, the temperature difference between the jacket part 452 and the jacket part 472 becomes large, and sufficient power generation is performed by the thermoelectric conversion element 49, the detection voltage becomes larger than the specified value. .

  If the control circuit 504 determines that the detected voltage is equal to or higher than the specified value (S102: YES), the switching element 502 is switched to the thermoelectric conversion element side, power is supplied from the thermoelectric conversion element 49, and the cooling fan 442 is driven ( S104).

  Thus, the liquid refrigerant circulates between the heat absorber 41 and the heat radiating unit 44, whereby heat transport from the heat absorber 41 to the heat radiating unit 44 is performed, and the light source device 21 is cooled.

  When the operation of the projector is stopped, the light emitting unit 211 is turned off accordingly. Immediately after the light is turned off, the light source device 21 is at a high temperature. Therefore, it is necessary to continue cooling the light source device 21 for a while.

  If it is determined that the light emitting unit 211 is turned off (S105: YES), the control circuit 504 operates the timer 505 (S106). The timer 505 measures the time required for cooling the light source device 21.

  When the control circuit 504 determines that the timer 505 has counted up (S107: YES), the control circuit 504 turns off the switching element 502 and stops power supply to the cooling fan 442 (S108). As a result, the cooling fan 442 stops.

  As described above, according to the present embodiment, the first transport path 45 in which the refrigerant of the high-temperature mixed fluid from the heat absorber 41 flows and the third transport path 47 in which the low-temperature liquid refrigerant from the heat dissipation unit 44 flows. Since the thermoelectric conversion elements 49 are arranged close to each other, the large temperature difference can be obtained stably, and stable power generation can be performed using the thermoelectric conversion elements 49.

  In addition, according to the present embodiment, since the cooling fan 442 is driven by the power supply from the thermoelectric conversion element 49, the cooling unit 40 with extremely low power consumption can be realized in combination with being pumpless. .

  Here, for the sake of comparison, it is assumed that the low temperature side substrate 492 is not mounted on the mounting surface of the jacket portion 472 as described above and is exposed to air. In this case, since the air in the vicinity of the upper portion of the heat absorber 41 is at a high temperature due to heat generated by the light source device 21, even if a low-temperature side substrate 492 is provided with heat radiation pins or the like and further blown, It is difficult to lower the temperature of 492 to the same extent as in the above embodiment. In the present embodiment, the low temperature side substrate 492 is effectively cooled by devising the piping as described above and mounting the low temperature side substrate 492 on the mounting surface of the jacket portion 472. Therefore, according to this embodiment, the temperature difference between the high temperature side substrate 491 and the low temperature side substrate 492 can be increased, and stable power generation can be performed using the thermoelectric conversion element 49.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  For example, in the above embodiment, the electric power of the thermoelectric conversion element 49 is used for driving the cooling fan 442. However, the electric power of the thermoelectric conversion element 49 is not limited to this. It may be used to drive the liquid crystal panels 23, 24, 25, and the like.

  In the present embodiment, the light source device 21 is cooled by the cooling unit 40. However, the present invention is not limited to this, and other highly heat-generating components such as the liquid crystal panels 23, 24, 25, etc. You may make it cool.

  Furthermore, the heat radiating unit 44 can be arranged at an arbitrary position in the housing 10. At this time, if the heat dissipating unit 44 is arranged so that the distance from the storage chamber 42 to the heat dissipating unit 44 is increased, the second transport path 46 can be lengthened. The heat dissipation of the liquid refrigerant can be performed. Thereby, since the cooling performance of the thermal radiation unit 44 can be reduced, the power consumption of the cooling fan 442 can be reduced and the thermoelectric conversion element 49 can be reduced in size.

  Furthermore, in the above embodiment, whether or not the cooling fan 442 can be properly driven by the control circuit 504 based on the detection voltage (voltage of the storage battery 501) from the voltage detection circuit 503, that is, the thermoelectric conversion element. It is configured to determine whether or not 49 is an appropriate amount of power generation. However, the means for determining whether or not the thermoelectric conversion element 49 has an appropriate power generation amount is not limited to such a configuration, and may be other means.

  For example, the temperature of the jacket 452 in the first transport path 45 may be detected by a temperature sensor (thermistor), and it may be determined whether or not the thermoelectric conversion element 49 has an appropriate power generation amount based on the detected temperature. In this case, if the control circuit 504 determines that the detected temperature is equal to or higher than the specified value, the power supply from the external power supply can be switched to the electrode supply from the thermoelectric conversion element 49.

  Furthermore, the light source device 21 is not limited to a lamp light source, and may be a laser light source, for example.

  Furthermore, in the above embodiment, the cooling unit 40 is mounted on the projector, but the cooling system of the present invention may be mounted on a device other than the projector.

  In addition, various modifications can be made as appropriate within the scope of the technical idea shown in the claims.

21 ... Light source device (light source)
212 ... Reflectors 23, 24, 25 ... Liquid crystal panel (display element)
40 ... Cooling unit (cooling system)
41 ... Heat absorber (heat absorption part)
412 ... Black paint (black layer)
42… Accommodating room (heat exchanger)
43 ... Heat exchanger (heat exchanger)
44… Heat dissipation unit (heat dissipation part)
442 ... Cooling fan (cooling fan)
45 ... 1st transportation route (high temperature side transportation route)
453 ... Heat insulating member 46 ... Second transport path 47 ... Third transport path (low temperature side transport path)
473 ... Heat insulating member 48 ... Fourth transport path 49 ... Thermoelectric conversion element

Claims (6)

An endothermic part that absorbs heat from the object to be cooled and changes the state of the refrigerant to a mixed fluid of liquid and gas, a heat dissipating part that releases heat from the liquid refrigerant, and an endothermic part disposed above the endothermic part. In a cooling system comprising: a heat exchange unit that performs heat exchange between the refrigerant of the mixed fluid generated by the unit and the liquid refrigerant radiated by the heat dissipation unit,
At least a part of the high temperature side transportation path connecting the heat absorption section and the heat exchange section and the low temperature side transportation path connecting the heat radiation section and the heat exchange section are arranged close to each other,
A thermoelectric conversion element disposed between the high temperature side transport path and the adjacent portion of the low temperature side transport path, and generating electric power due to a temperature difference between the high temperature side transport path and the low temperature side transport path;
A cooling system characterized by that. The cooling system of claim 1, wherein
A cooling system comprising a cooling fan arranged in the heat radiating section and driven by electric power from the thermoelectric conversion element. The cooling system according to claim 1 or 2,
A cooling system comprising a heat insulating member for suppressing heat transfer in the adjacent portion of the high temperature side transport path and the low temperature side transport path.   A projection display apparatus comprising the cooling system according to any one of claims 1 to 3. The projection display apparatus according to claim 4, wherein
A projection display apparatus, wherein the object to be cooled is a light source. The projection display apparatus according to claim 5, wherein
The light source includes a reflector that reflects visible light and transmits other light,
The heat absorption part has a black layer formed on the surface in contact with the reflector,
A projection display apparatus characterized by the above.

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