Patent Publication Number: US-11029588-B2

Title: Projector

Description:
The present application is based on, and claims priority from JP Application Serial Number 2019-133435, filed Jul. 19, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a projector. 
     2. Related Art 
     As a device for cooling a projector, there are proposed such a cooloer due to air cooling using a blower as described in, for example, JP-A-2002-107698, such a cooloer due to liquid cooling using a pump for feeding a refrigerant liquid and a pipe for transmitting the refrigerant liquid as described in, for example, JP-A-2007-294655, and so on. 
     In recent years, due to an increase in luminance of projectors, an amount of heat of a cooling target to be cooled by a cooloer has increased, and an improvement in cooling performance of the cooloer is required. However, when improving the cooling performance in the cooloer described above using air cooling, liquid cooling, and so on, there is a problem that the cooloer grows in size, and thus the projector grows in size. Further, in the case of air cooling, there is also a problem that the sound noise due to the blower increases. 
     SUMMARY 
     A projector according to an aspect of the present disclosure is a projector having a cooling target, including a light source configured to emit light, a light modulator configured to modulate the light emitted from the light source, a projection optical device configured to project the light modulated by the light modulator, and a cooloer configured to cool the cooling target based on transformation of a refrigerant into a gas. The cooloer includes a refrigerant generator configured to generate the refrigerant from air, a refrigerant sender configured to transmit the refrigerant generated toward the cooling target, and a first duct configured to guide air including the refrigerant changed to a gas in the cooling target toward the refrigerant generator. 
     The projector may be configured such that the cooloer includes a cooling blower configured to deliver air to the cooling target, and the first duct guides, toward the refrigerant generator, the air after being deliverd from the cooling blower to the cooling target flow. 
     The projector may be configured such that the refrigerant generator includes a rotating moisture absorption/desorption member, a first blower configured to deliver air to a first part of the moisture absorption/desorption member located in a first area, a heat exchanger coupled to the refrigerant sender, a heater configured to heat a second part of the moisture absorption/desorption member located in a second area different from the first area, and a second blower configured to feed ambient air of the part heated by the heater in the moisture absorption/desorption member to the heat exchanger. The heat exchanger is cooled to thereby generate the refrigerant from the air flowed into the heat exchanger, and the first duct guides, toward the moisture absorption/desorption member, the air after being deliberd from the cooling blower to the cooling target. 
     The projector may be configured such that the refrigerant generator has a second duct configured to guide the air deliverd from the first blower flow toward the moisture absorption/desorption member, and an end part at downstream of the first duct in a flow direction of air flowing inside the first duct is coupled to the second duct. 
     The projector may be configured such that the first blower is the cooling blower, and the first blower delivers, to the cooling target, air after passing the first part of the moisture absorption/desorption member. 
     The projector may be configured such that the projector further includes a dust-proof case configured to house at least apart of the cooling target inside. The cooling target includes a cooling target main body part, and a cooling target part which is thermally coupled to the cooling target main body part, and to which the refrigerant is transmitted from the refrigerant sender. The cooling target main body part is disposed inside the dust-proof case. The cooling target part is disposed inside the first dust in an outside of the dust-proof case, and air deliverd from the cooling blower inflows into the first duct. 
     The projector may be configured such that the projector further includes a light modulation unit including the light modulator and a holding frame configured to hold the light modulator. The holding frame includes a frame main body part configured to hold the light modulator, and an extending part extending from the frame main body part. The light modulation unit corresponds to the cooling target, the light modulator corresponds to the cooling target main body part, and the extending part corresponds to the cooling target part. 
     The projector may be configured such that the cooling target is the light modulator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic configuration diagram showing a projector according to a first embodiment. 
         FIG. 2  is a schematic diagram showing a part of the projector according to the first embodiment. 
         FIG. 3  is a schematic configuration diagram schematically showing a refrigerant generator in the first embodiment. 
         FIG. 4  is a perspective view showing a moisture absorption/desorption member in the first embodiment. 
         FIG. 5  is a partial cross-sectional perspective view showing a heat exchanger in the first embodiment. 
         FIG. 6  is a perspective view showing light modulation units, a light combining optical system, and a dust-proof case in the first embodiment. 
         FIG. 7  is a diagram showing a refrigerant holder in the first embodiment. 
         FIG. 8  is a cross-sectional view showing the light modulation units, the dust-proof case, and a part of a first duct in the first embodiment, and is a VIII-VIII cross-sectional view in  FIG. 6 . 
         FIG. 9  is a schematic configuration diagram schematically showing a part of a cooloer in a second embodiment. 
         FIG. 10  is a cross-sectional view of light modulation units and a part of a first duct in a third embodiment viewed from an upper side. 
         FIG. 11  is a cross-sectional view of light modulation units and a part of a first duct in a fourth embodiment viewed from an upper side. 
         FIG. 12  is a cross-sectional view showing light modulation units, a dust-proof case, and a part of a first duct in a fifth embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A projector according to an embodiment of the present disclosure will hereinafter be described with reference to the drawings. It should be noted that the scope of the present disclosure is not limited to the embodiments hereinafter described, but can arbitrarily be modified within the technical idea or the technical concept of the present disclosure. Further, in the following drawings, in order to make each constituent easy to understand, each of the structures is made different from the actual structure in scale size, number, and so on in some cases. 
     First Embodiment 
       FIG. 1  is a schematic configuration diagram showing the projector  1  according to the present embodiment.  FIG. 2  is a schematic diagram showing a part of the projector  1  according to the present embodiment. As shown in  FIG. 1 , the projector  1  is provided with a light source device  2 , a color separation optical system  3 , a light modulation unit  4 R, a light modulation unit  4 G, a light modulation unit  4 B, a light combining optical system  5 , and a projection optical device  6 . The light modulation unit  4 R has a light modulator  4 RP. The light modulation unit  4 G has a light modulator  4 GP. The light modulation unit  4 B has a light modulator  4 BP. 
     The light source device  2  emits illumination light WL regulated so as to have a substantially homogenous illuminance distribution toward the color separation optical system  3 . The light source device  2  has, for example, a semiconductor laser as a light source. The color separation optical system  3  separates the illumination light WL from the light source device  2  into red light LR, green light LG, and blue light LB. The color separation optical system  3  is provided with a first dichroic mirror  7   a,  a second dichroic mirror  7   b,  a first reflecting mirror  8   a,  a second reflecting mirror  8   b,  a third reflecting mirror  8   c,  and a relay lens  8   d.    
     The first dichroic mirror  7   a  separates the illumination light WL having been emitted from the light source device  2  into the red light LR, and the light including the green light LG and the blue light LB mixed with each other. The first dichroic mirror  7   a  has a property of transmitting the red light LR, while reflecting the green light LG and the blue light LB. The second dichroic mirror  7   b  separates the light including the green light LG and the blue light LB mixed with each other into the green light LG and the blue light LB. The second dichroic mirror  7   b  has a property of reflecting the green light LG, while transmitting the blue light LB. 
     The first reflecting mirror  8   a  is disposed in the light path of the red light LR, and the red light LR having been transmitted through the first dichroic mirror  7   a  is reflected by the first reflecting mirror  8   a  toward the light modulator  4 RP. The second reflecting mirror  8   b  and the third reflecting mirror  8   c  are disposed in the light path of the blue light LB, and the blue light LB having been transmitted through the second dichroic mirror  7   b  is guided by the second reflecting mirror  8   b  and the third reflecting mirror  8   c  to the light modulator  4 BP. 
     The light modulator  4 RP, the light modulator  4 GP, and the light modulator  4 BP are each formed of a liquid crystal panel. The light modulator  4 RP modulates the red light LR out of the light emitted from the light source device  2  in accordance with an image signal. The light modulator  4 GP modulates the green light LG out of the light emitted from the light source device  2  in accordance with an image signal. The light modulator  4 BP modulates the red light LB out of the light emitted from the light source device  2  in accordance with an image signal. Thus, the light modulators  4 RP,  4 GP, and  4 BP each form image light corresponding to the colored light. Although not shown in the drawings, on the light incident side and the light exit side of each of the light modulators  4 RP,  4 GP, and  4 BP, there are respectively disposed polarization plates. 
     On the light incident side of the light modulator  4 RP, there is disposed a field lens  9 R for collimating the red light LR entering the light modulator  4 RP. On the light incident side of the light modulator  4 GP, there is disposed a field lens  9 G for collimating the green light LG entering the light modulator  4 GP. On the light incident side of the light modulator  4 BP, there is disposed a field lens  9 B for collimating the blue light LB entering the light modulator  4 BP. 
     The color combining optical system  5  is formed of across dichroic prism having a substantially cubic shape. The light combining optical system  5  combines the image light of the respective colors from the light modulators  4 RP,  4 GP, and  4 BP with each other. The light combining optical system  5  emits the image light thus combined toward the projection optical device  6 . The projection optical device  6  is formed of a projection lens group. The projection optical device  6  projects the image light combined by the light combining optical system  5 , namely the light modulated by the light modulators  4 RP,  4 GP, and  4 BP, toward a screen SCR in an enlarged manner. Thus, a color image (picture) thus enlarged is displayed on the screen SCR. 
     As shown in  FIG. 2 , the projector  1  is further provided with a cooloer  10 . The cooloer  10  cools a cooling target provided to the projector  1  by a refrigerant W changing to a gas. In the present embodiment, the refrigerant W is, for example, water as a fluid. Therefore, in the following description, the change of the refrigerant W to the gas is simply referred to as evaporation in some cases. In the present embodiment, the cooling target includes the light modulation units  4 R,  4 G, and  4 B. In other words, in the present embodiment, the cooling target includes the light modulators  4 RP,  4 GP, and  4 BP. In the present embodiment, the light modulators  4 RP,  4 GP, and  4 BP correspond to a cooling target main body part. 
     The cooloer  10  has a refrigerant generator  20  and a refrigerant sender  50 . The refrigerant generator  20  is a section for generating the refrigerant W from the air. The refrigerant sender  50  is a section for transmitting the refrigerant W thus generated toward the cooling target. Due to the evaporation of the refrigerant W having been transmitted by the refrigerant sender  50  to the cooling target, namely the light modulation units  4 R,  4 G, and  4 B in the present embodiment, it is possible to draw the heat from the cooling target, and thus, it is possible for the cooloer  10  to cool the cooling target. Each of the sections will hereinafter be described in detail. 
       FIG. 3  is a schematic configuration diagram schematically showing a refrigerant generator  20  in the present embodiment. As shown in  FIG. 3 , the refrigerant generator  20  has a moisture absorption/desorption member  40 , a motor (a driver)  24 , a first blower (a cooling blower)  60 , a second duct  62 , a heat exchanger  30 , a circulation duct  25 , a circulation duct  26 , a heater  22 , a second blower  23 , a third blower  28 , and a cooling duct  21 . 
       FIG. 4  is a perspective view showing the moisture absorption/desorption member  40 . As shown in  FIG. 4 , the moisture absorption/desorption member  40  has a flat cylindrical shape centered on a rotational axis R. Ina central part of the moisture absorption/desorption member  40 , there is formed a central hole  40   c  centered on the rotational axis R. The central hole  40   c  penetrates the moisture absorption/desorption member  40  in an axial direction of the rotational axis R. The moisture absorption/desorption member  40  rotates around the rotational axis R. In the following description, the axial direction of the rotational axis R is referred to as a “rotational axis direction DR,” and is arbitrarily represented by a DR axis in the drawings. 
     The moisture absorption/desorption member  40  has an infinitely large number of through holes  40   b  penetrating the moisture absorption/desorption member  40   b  in the rotational axis direction DR. The moisture absorption/desorption member  40  is a porous member. The moisture absorption/desorption member  40  has a moisture absorption/desorption property. In the present embodiment, the moisture absorption/desorption member  40  is manufactured by, for example, winding a belt-like member  40   a  shaped like a belt and having the through holes  40   b  around the rotational axis R, and then coating a surface exposed outside in the belt-like member  40   a  thus wound with a material having a moisture absorption/desorption property. It should be noted that the surface exposed outside in the belt-like member  40   a  thus wound includes an outside surface of the moisture absorption/desorption member  40 , an inner circumferential surface of the central hole  40   c,  and internal surfaces of the through holes  40   b.  It should be noted that the moisture absorption/desorption member  40  can wholly be made of a material provided with the moisture absorption/desorption property. As the material having the moisture absorption/desorption property, there can be cited, for example, zeolite and silica gel. 
     An output shaft of the motor  24  shown in  FIG. 3  is fixed in a state of being inserted into the central hole  40   c  of the moisture absorption/desorption member  40 . The motor  24  rotates the moisture absorption/desorption member  40  around the rotational axis R. The rotational speed of the moisture absorption/desorption member  40  rotated by the motor  24  is, for example, about no lower than 0.2 rpm and no higher than 5 rpm. 
     The first blower  60  is, for example, an intake fan for taking external air in the projector  1 . The first blower  60  feeds air AR 1  to apart of the moisture absorption/desorption member  40  located in a first area F 1 . The first area F 1  is an area on one side of the rotational axis R in a direction perpendicular to the rotational axis R. In contrast, in the direction perpendicular to the rotational axis R, an area on the other side of the rotational axis R, namely an area on the opposite side to the first area F 1  with respect to the rotational axis R, corresponds to a second area F 2 . The first area F 1  is an area on the upper side of the rotational axis R in  FIG. 3 . The second area F 2  is an area on the lower side of the rotational axis R in  FIG. 3 . 
     As shown in  FIG. 3 , the first blower  60  feeds the air AR 1  also to the light modulation units  4 R,  4 G, and  4 B as the cooling target. In other words, in the present embodiment, the first blower  60  is a cooling blower for feeding the air AR 1  to the cooling target. In the present embodiment, the first blower  60  feeds the air AR 1  which has passed through a part of the moisture absorption/desorption member  40  located in the first area F 1  to the cooling target. The first blower  60  is not particularly limited providing the first blower  60  is capable of feeding the air AR 1 , and can be, for example, an axial fan or a centrifugal fan. 
     The second duct  62  is a duct which makes the air AR 1  fed from the first blower  60  flow toward the moisture absorption/desorption member  40 . In the present embodiment, the second duct  62  is located on the other side (−DR side) of the moisture absorption/desorption member  40  in the rotational axis direction DR. The second duct  62  extends in the rotational axis direction DR, and opens on both sides in the rotational axis direction DR. An end part on one side (+DR side) in the rotational axis direction DR in the second duct  62  is opposed to the part of the moisture absorption/desorption member  40  located in the first area F 1  with a gap. In the second duct  62  in the present embodiment, the air AR 1  flows from the other side (−DR side) to the one side (+DR side) in the rotational axis direction DR. 
     The heat exchanger  30  is a section where the refrigerant W is generated.  FIG. 5  is a partial cross-sectional perspective view showing the heat exchanger  30 . As shown in  FIG. 5 , the heat exchanger  30  has a flowing part  31 , a first lid part  32 , and a second lid part  33 . 
     The flowing part  31  has a plurality of pipe parts  31   a  each having a tubular shape extending in one direction. In the present embodiment, the one direction in which the pipe parts  31   a  extend is, for example, perpendicular to the rotational axis direction DR. The pipe parts  31   a  each open on both sides in the one direction in which the pipe parts  31   a  extend. A shape of a cross-sectional surface of the pipe part  31   a  perpendicular to the one direction in which the pipe parts  31   a  extend is, for example, a circular shape. It should be noted that in the following description, the one direction in which the pipe parts  31   a  extend is referred to as an “extension direction DE,” and is arbitrarily represented by a DE axis in the drawings. The first area F 1  and the second area F 2  described above are separated in the extension direction DE perpendicular to the rotational axis direction DR with reference to the rotational axis R. 
     In the present embodiment, the flowing part  31  is formed of a plurality of layers each formed of the plurality of pipe parts  31   a  arranged along the rotational axis direction DR stacked along a direction perpendicular to both of the rotational axis direction DR and the extension direction DE. It should be noted that in the following description, the direction perpendicular to both of the rotational axis direction DR and the extension direction DE is referred to as a “thickness direction DT,” and is arbitrarily represented by a DT axis in the drawings. In the present embodiment, the dimension in the thickness direction DT of the flowing part  31  is smaller than, for example, the dimension in the rotational axis direction DR of the flowing part  31 , and is the smallest of the dimensions of the flowing part  31  in the direction perpendicular to the extension direction DE. 
     The first lid part  32  is coupled to an end part on one side (+DE side) in the extension direction DE in the flowing part  31 . The first lid part  32  has a rectangular solid box-like shape elongated in the rotational axis direction DR. Inside the first lid part  32 , one ends in the extension direction DE of the pipe parts  31   a  open. As shown in  FIG. 3 , inside the first lid part  32 , there is disposed a partition part  32   a.  The partition part  32   a  separates the inside of the first lid part  32  into a first space Si and a second space S 2  arranged side by side in the rotational axis direction DR. In  FIG. 3 , the first space Si is located on the right side (+DR side) of the second space S 2 . 
     The first lid part  32  is provided with a communication hole  32   b  for communicating the first space Si and the inside of the circulation duct  26  with each other. The first lid part  32  is provided with a communication hole  32   c  for communicating the second space S 2  and the inside of the circulation duct  25  with each other. 
     The second lid part  33  is coupled to an end part on the other side (−DE side) in the extension direction DE in the flowing part  31 , namely an end part on an opposite side to the side where the first lid part  32  is coupled to the flowing part  31 . As shown in  FIG. 5 , the second lid part  33  has a rectangular solid box-like shape elongated in the rotational axis direction DR. Inside the second lid part  33 , the other ends in the extension direction DE of the pipe parts  31   a  open. Unlike the first lid part  32 , the inside of the second lid part  33  is not partitioned. The inside of the second lid part  33  is communicated with each of the first space Si and the second space S 2  of the first lid part  32  via the inside of each of the pipe parts  31   a  of the flowing part  31 . The second lid part  33  is coupled to the refrigerant sender  50 . Thus, the heat exchanger  30  is coupled to the refrigerant sender  50 . It should be noted that in  FIG. 5 , a wall on the other side in the extension direction DE in the second lid part  33  is omitted. 
     As shown in  FIG. 3 , the circulation duct  26  is a duct disposed on the one side (+DR side) of the moisture absorption/desorption member  40  in the rotational axis direction DR. The circulation duct  26  has an inflow port opening on the other side (−DR side) in the rotational axis direction DR toward a part of the moisture absorption/desorption member  40  located in the second area F 2 . The circulation duct  26  has an outflow port to be communicated with the communication hole  32   b  of the first lid part  32 . 
     The circulation duct  25  is a duct disposed on the other side (−DR side) of the moisture absorption/desorption member  40  in the rotational axis direction DR. The circulation duct  25  has an outflow port opening on the one side (+DR side) in the rotational axis direction DR toward the part of the moisture absorption/desorption member  40  located in the second area F 2 . The circulation duct  25  has an inflow port to be communicated with the communication hole  32   c  of the first lid part  32 . 
     The heater  22  has a heating main body part  22   a.  The heating main body part  22   a  is disposed inside the circulation duct  25 . The heating main body part  22   a  is disposed on the other side (−DR side) of the part of the moisture absorption/desorption member  40  located in the second area F 2  in the rotational axis direction DR. The heating main body part  22   a  is, for example, an electric heater. The heating main body part  22   a  heats an inside atmosphere (air) of the circulation duct  25 . In the present embodiment, the heater  22  has the second blower  23 . 
     The second blower  23  is disposed inside the circulation duct  26 . The second blower  23  is disposed on the one side (+DR side) of the part of the moisture absorption/desorption member  40  located in the second area F 2  in the rotational axis direction DR. The second blower  23  is, for example, a centrifugal fan. The air taken from the other side (−DR side) in the rotational axis direction DR is discharged by the second blower  23  toward the other side (−DE side) in the extension direction DE from an exhaust port  23   a.  The exhaust port  23   a  opens in the communication hole  32   b  of the first lid part  32 . The second blower  23  feeds the air to the first space S 1  via the communication hole  32   b.    
     The air discharged from the second blower  23  to the first space S 1  is the air having been taken in from the other side (−DR side) in the rotational axis direction DR of the second blower  23  via the inflow port of the circulation duct  26 , and is the air having passed through the part of the moisture absorption/desorption member  40  located in the second area F 2 . In other words, the second blower  23  makes the air pass through the part of the moisture absorption/desorption member  40  located in the second area F 2  different from the first area F 1 , and then feeds the air to the heat exchanger  30 . In the present embodiment, the air which has not passed the part of the moisture absorption/desorption member  40  located in the second area F 2  flows inside the circulation duct  25 . Therefore, the heating main body part  22   a  heats the air which has not passed the part of the moisture absorption/desorption member  40  located in the second area F 2 . 
     As described above, in the present embodiment, the heater  22  feeds the air which has been heated by the heating main body part  22   a  to the part of the moisture absorption/desorption member  40  located in the second area F 2  by the second blower  23  to thereby heat the part of the moisture absorption/desorption member  40  located in the second area F 2 . Thus, the second blower  23  feeds the ambient air of the part heated by the heater  22  in the moisture absorption/desorption member  40  to the heat exchanger  30 . 
     The air which has flowed into the heat exchanger  30  from the second blower  23  via the first space Si passes inside the pipe parts  31   a  communicated with the first space Si out of the plurality of pipe parts  31   a,  and then inflows into the inside of the second lid part  33 . The air which has flowed into the inside of the second lid part  33  passes through the inside of the pipe parts  31   a  communicated with the second space S 2  out of the plurality of pipe parts  31   a,  then inflows into the second space S 2 , and then inflows into the inside of the circulation duct  25  from the communication hole  32   c.  The air having flowed into the inside of the circulation duct  25  is heated by the heating main body part  22   a,  then passes through the part of the moisture absorption/desorption member  40  located in the second area F 2  once again, then inflows into the inside of the circulation duct  26 , and is then taken in by the second blower  23 . 
     As described hereinabove, in the present embodiment, the refrigerant generator  20  has a circulation channel  27  through which the air discharged from the second blower  23  circulates. The circulation channel  27  is constituted by at least the circulation ducts  25 ,  26  and the heat exchanger  30 . The circulation channel  27  passes the heating main body part  22   a,  the moisture absorption/desorption member  40 , and the heat exchanger  30 . Although a narrow gap is provided between the moisture absorption/desorption member  40  and each of the circulation ducts  25 , the circulation channel  27  is substantially sealed, and thus, the air from the outside is prevented from inflowing into the inside of the circulation channel  27 . It should be noted that in the following description, the air which has been discharged from the second blower  23  and then circulates through the circulation channel  27  is referred to as air AR 2 . 
     The third blower  28  is a blower for feeding air AR 3  to the heat exchanger  30  to cool the heat exchanger  30 . In the present embodiment, the third blower  28  is located on the one side (+DR side) in the rotational axis direction DR in the heat exchanger  30 , and feeds the air AR 3  toward the other side (−DR side) in the rotational axis direction DR. The air AR 3  having been fed from the third blower  28  is made to blow against an outer surface of the flowing part  31 . Thus, the flowing part  31  is cooled by the air AR 3 . 
     The cooling duct  21  is a duct for guiding the air AR 3  fed from the third blower  28  to the flowing part  31  of the heat exchanger  30 . In the present embodiment, the second duct  21  extends in the rotational axis direction DR, and opens on both sides in the rotational axis direction DR. In the cooling duct  21 , there is disposed the flowing part  31  of the heat exchanger  30  so as to penetrate in the extension direction DE. Thus, in the inside of the cooling duct  21 , there is disposed the flowing part  31 . Therefore, the air AR 3  flowing inside the cooling duct  21  is made to blow against the outer surface of the flowing part  31 . 
     When the air AR 1  is fed to the part of the moisture absorption/desorption member  40  located in the first area F 1  from the first blower  60 , the steam included in the air AR 1  is absorbed by the part of the moisture absorption/desorption member  40  located in the first area F 1 . The part of the moisture absorption/desorption member  40  having absorbed the steam as the moisture moves from the first area F 1  to the second area F 2  by the motor  24  rotating the moisture absorption/desorption member  40 . Then, through the part of the moisture absorption/desorption member  40  located in the second area F 2 , there passes the air AR 2  which has been heated by the heating main body part  22   a,  and is relatively high in temperature. Thus, the moisture having been absorbed by the moisture absorption/desorption member  40  evaporates to be released to the air AR 2 . 
     The air AR 2  including the steam which has been absorbed from the air AR 1  by passing through the moisture absorption/desorption member  40  is fed by the second blower  23  to the heat exchanger  30 . The air AR 2  having flowed into the heat exchanger  30  from the first space Si flows through the flowing part  31 . More particularly, the air AR 2  flows through the pipe parts  31   a  of the flowing part  31 . The flowing part  31  is cooled from the outside by the air AR 3  flowing along the rotational axis direction DR through the cooling duct  21 . 
     When the flowing part  31  is cooled, the air AR 2  which flows through the pipe parts  31   a  and is relatively high in temperature is cooled, and thus, the steam having been included in the air AR 2  is condensed to the water as a fluid, namely the refrigerant W. In such a manner, the heat exchanger  30  is cooled to thereby generate the refrigerant W from the air AR 2  having flowed into the heat exchanger  30 . 
     In the present embodiment, the refrigerant sender  50  is formed of a porous member, and transmits the refrigerant W due to a capillary action. As the material of the refrigerant sender  50 , there can be cited, for example, polypropylene, cotton, and porous metal. It is preferable for the material of the refrigerant sender  50  to be a material capable of making the surface tension of the refrigerant sender  50  relatively high. As shown in  FIG. 5 , the refrigerant sender  50  has a first trapping part  51 , a second trapping part  52 , a third trapping part  53 , and a coupling part  54 . 
     The first trapping part  51  is fixed to an edge part on the one side (+DE side) in the extension direction DE in the inside surface of the first lid part  32 . The first trapping part  51  is shaped like a thin belt, and is formed along the edge part of the first lid part  32  to have a rectangular frame shape. The second trapping part  52  is fixed to an edge part on the other side (−DE side) in the extension direction DE in the inside surface of the second lid part  33 . The second trapping part  52  is shaped like a thin belt, and is formed along the edge part of the second lid part  33  to have a rectangular frame shape. 
     The third trapping part  53  extends from the first trapping part  51  to the second trapping part  52  through the inside of the pipe part  31   a  to couple the first trapping part  51  and the second trapping part  52  to each other. The third trapping part  53  is shaped like a thin belt extending in the extension direction DE. In the present embodiment, the third trapping part  53  is disposed inside one of the pipe parts  31   a  as shown in  FIG. 5 , but this is not a limitation. The third trapping part  53  can be disposed inside some of the pipe parts  31   a,  or can also be disposed inside all of the pipe parts  31   a.  When the third trapping part  53  is disposed inside some of the pipe parts  31   a,  it is also possible for the third trapping part  53  to be disposed inside two or more of the pipe parts  31   a.    
     The coupling part  54  is a part for coupling the refrigerant generator  20  and the cooling target to each other. In the present embodiment, the coupling part  54  is coupled to the second trapping part  52 , and projects from the inside of the second lid part  33  to the outside of the second lid part  33  so as to penetrate the wall of the second lid part  33 . As shown in  FIG. 6 , the coupling part  54  projecting to the outside of the second lid part  33  extends to the light modulation unit  4 G as the cooling target.  FIG. 6  is a perspective view showing the light modulation units  4 R,  4 G, and  4 B, the light combining optical system  5 , and a dust-proof case  90  described later. The coupling part  54  is shaped like a thin belt. The width of the coupling part  54  is larger than, for example, the width of the first trapping part  51 , the width of the second trapping part  52 , and the width of the third trapping part  53 . 
     As shown in  FIG. 3 , in the present embodiment, the cooloer  10  has a first duct  61 . The first duct  61  is coupled to the second duct  62 . More particularly, the first duct  61  extends from the area on the one side (+DR side) in the rotational axis direction DR in the moisture absorption/desorption member  40  toward the one side in the rotational direction DR, and is then folded back toward the other side (−DR side) in the rotational axis direction DR to extend to the other side in the rotational axis direction DR beyond the moisture absorption/desorption member  40 , and is then coupled to the second duct  62 . In the present embodiment, the first duct  61  includes a first flow channel part  61   a,  a second flow channel part  61   b,  a third flow channel part  61   c,  and a fourth flow channel part  61   d.    
     The first flow channel part  61   a  is located on the one side (+DR side) in the rotational axis direction DR in the moisture absorption/desorption member  40 . The first flow channel part  61   a  extends in the rotational axis direction DR. An end part on the other side (−DR side) in the rotational axis direction DR in the first flow channel part  61   a  opens, and is opposed to the part of the moisture absorption/desorption member  40  located in the first area F 1  with a gap. Inside the first flow channel part  61   a,  there is disposed the extending parts  82  described later out of the light modulation units  4 R,  4 G, and  4 B. It should be noted that in  FIG. 3 , there is schematically shown the extending part  82 . 
     The second flow channel part  61   b  extends from an end part on the one side (+DR side) in the rotational axis direction DR in the first flow channel part  61   a  toward the one side (+DE side) in the extension direction DE. The third flow channel part  61   c  extends from an end part on the one side in the extension direction DE in the second flow channel part  61   b  toward the other side (−DR side) in the rotational axis direction DR. The third flow channel part  61   c  extends to the other side in the rotational axis direction DR beyond the moisture absorption/desorption member  40 . The fourth flow channel part  61   d  extends from an end part on the other side in the rotational axis direction DR in the third flow channel part  61   c  toward the other side (−DE side) in the extension direction DE. An end part on the other side in the extension direction DE in the fourth flow channel part  61   d  is coupled to the second duct  62 . 
     The air AR 1  having flowed into the second duct  62  from the first blower  60  passes the part of the moisture absorption/desorption member  40  located in the first area F 1 , and then inflows into the first flow channel part  61   a  in the first duct  61 . In other words, into the first duct  61 , there inflows the air AR 1  from the first blower  60 . The air AR 1  having flowed into the first duct  61  flows through the first flow channel part  61   a,  the second flow channel part  61   b,  the third flow channel part  61   c,  and the fourth flow channel part  61   d  in this order, and then inflows into the second duct  62 . In other words, in the present embodiment, an end part on the other side (−DE side) in the extension direction DE in the fourth flow channel part  61   d  corresponds to an end part at downstream of the first duct  61  in the flow direction of the air AR 1  flowing inside the first duct  61 . The air AR 1  having flowed into the second duct  62  from the first duct  61  merges with the air AR 1  having flowed into the second duct  62  from the first blower  60 , and is then fed to the moisture absorption/desorption member  40  once again. 
     Then, the light modulation units  4 R,  4 G, and  4 B as the cooling target in the present embodiment will be described in more detail. In the following description, an up-and-down direction Z defining a positive side as an upper side and a negative side as a lower side is arbitrarily represented by a Z axis in the drawings. A direction parallel to an optical axis AX of a projection lens the closest to the light exit side in the projection optical device  6 , namely a direction parallel to the projection direction of the projection optical device  6 , is referred to as an “optical axis direction X,” and is arbitrarily represented by an X axis in the drawings. The optical direction X is perpendicular to the up-and-down direction Z. Further, a direction perpendicular to both of the optical axis direction X and the up-and-down direction Z is referred to as a “width direction Y,” and is arbitrarily represented by a Y axis in the drawings. 
     It should be noted that the up-and-down direction Z, the upper side, and the lower side are mere names for explaining the relative positional relationship between the constituents, and the actual arrangement relationship and so on can also be other arrangement relationships and so on than the arrangement relationships and so on represented by these names. Further, in the present embodiment, there is described when the up-and-down direction Z is a vertical direction. 
     As shown in  FIG. 6 , the light modulation unit  4 R, the light modulation unit  4 G, and the light modulation unit  4 B as the cooling target are disposed so as to surround the light combining optical system  5 . The light modulation unit  4 R and the light modulation unit  4 B are disposed across the light combining optical system  5  from each other in the width direction Y. The light modulation unit  4 R and the light modulation unit  4 B are disposed so as to be symmetric with respect to the width direction Y to each other. The light modulation unit  4 G is disposed on the light incident side (−X side) in the optical axis direction X of the light combining optical system  5 . The posture of the light modulation unit  4 G is a posture obtained by rotating the light modulation unit  4 R counterclockwise as much as  90 ° viewed from the upper side. 
     In the light modulation unit  4 R, the direction of the light passing through the light modulator  4 RP is parallel to the width direction Y. In the light modulation unit  4 R, a positive side (+Y side) in the width direction Y is the light incident side on which the light enters the light modulator  4 RP, and a negative side (−Y side) in the width direction Y is the light exit side on which the light is emitted from the light modulator  4 RP. 
     In the light modulation unit  4 G, the direction of the light passing through the light modulator  4 GP is parallel to the optical axis direction X. In the light modulation unit  4 G, a negative side (−X side) in the optical axis direction X is the light incident side on which the light enters the light modulator  4 GP, and a positive side (+X side) in the optical axis direction X is the light exit side on which the light is emitted from the light modulator  4 GP. 
     In the light modulation unit  4 B, the direction of the light passing through the light modulator  4 BP is parallel to the width direction Y. In the light modulation unit  4 B, a negative side (−Y side) in the width direction Y is the light incident side on which the light enters the light modulator  4 BP, and a positive side (+Y side) in the width direction Y is the light exit side on which the light is emitted from the light modulator  4 BP. 
     The light modulation units  4 R,  4 G, and  4 B and cooling promoters  70  described later and respectively provided to the light modulation units  4 R,  4 G, and  4 B have substantially the same shapes although different from each other in the arrangement position and the posture. Therefore, in the following description, only the light modulation unit  4 G and the cooling promoter  70  provided to the light modulation unit  4 G are described as the representative in some cases unless otherwise noted. 
     The light modulation units  4 R,  4 G, and  4 B have holding frames  80  for holding the light modulators  4 RP,  4 GP, and  4 BP, respectively. The holding frames  80  of the light modulation units  4 R,  4 G, and  4 B are different in arrangement and posture from each other so as to correspond to the arrangements and the postures of the light modulation units  4 R,  4 G, and  4 B, but have substantially the same shapes as each other. 
     The holding frame  80  provided to the light modulation unit  4 G has a shape flat in the optical axis direction X in which the light passes through the light modulator  4 GP, and elongated in the up-and-down direction Z. The holding frame  80  has a frame main body part  81 , an extending part (a cooling target part)  82 , and support parts  83 . The frame main body part  81  is a part for holding the light modulator  4 GP. The frame main body part  81  has a rectangular frame shape having a through hole  81   a  penetrating the frame main body part  81  in the optical axis direction X. In the through hole  81   a,  there is fitted the light modulator  4 GP. Thus, the light modulator  4 GP is held by the holding frame  80  with the outer peripheral edge part held by the frame main body part  81 . 
     The extending part  82  is a part extending from the frame main body part  81 . In the present embodiment, the extending part  82  extends upward from a region located on the light exit side (+X side) out of an upper end part of the frame main body part  81 . The extending part  82  is disposed on the upper side (+Z side) in the vertical direction (the Z-axis direction) of the light modulator  4 GP. The dimension in the optical axis direction X of the extending part  82  is smaller than the dimension in the optical axis direction X of the frame main body part  81 . In the present embodiment, the extending part  82  is the cooling target part to which the refrigerant W is transmitted from the refrigerant sender  50 . In other words, the light modulation units  4 R,  4 G, and  4 B corresponding to the cooling target in the present embodiment include the light modulators  4 RP,  4 GP, and  4 BP corresponding to the cooling target main body part, and the extending parts  82  corresponding to the cooling target parts, respectively. 
     The extending part  82  is thermally coupled to the light modulator  4 GP as the cooling target main body part via the frame main body part  81 . It should be noted that in the present specification, the sentence “certain objects are thermally coupled to each other” is sufficiently satisfied when the certain objects are coupled to each other in a state in which the heat transfer is achievable between the certain objects. In other words, the heat of the light modulator  4 GP can be transferred to the extending part  82  via the frame main body part  81 . 
     The extending part  82  includes a first part  82   a,  a second part  82   b,  and a third part  82   c.  The first part  82   a,  the second part  82   b,  and the third part  82   c  are contiguous with one another in this order from the lower side toward the upper side. The first part  82   a,  the second part  82   b,  and the third part  82   c  each have a rectangular solid shape elongated in the width direction Y perpendicular to both of the up-and-down direction Z and the optical axis direction X in which the light passes through the light modulator  4 GP. 
     The dimension in the width direction Y of the first part  82   a  is the same as the dimension in the width direction Y of the frame main body part  81 . The dimension in the width direction Y of the second part  82   b  is smaller than the dimension in the width direction Y of the first part  82   a.  The dimension in the width direction Y of the third part  82   c  is larger than the dimension in the width direction Y of the first part  82   a  and the dimension in the width direction Y of the second part  82   b.  The third part  82   c  projects on both sides in the width direction Y from the second part  82   b.    
     The support parts  83  project from the first part  82   a  of the extending part  82  toward the light incident side (−X side). The support parts  83  are disposed as a pair at an interval in the width direction Y. An end part on the lower side of each of the support parts  83  is coupled to a surface on the upper side of the frame main body part  81 . The support parts  83  support a refrigerant holder  71  described later and a fixation member  72  from the lower side. 
     In the present embodiment, the holding frames  80  are each made of metal. The material of the holding frames  80  includes, for example, aluminum. In the present embodiment, the thermal conductivity of the holding frames  80  is higher than the thermal conductivity of the refrigerant sender  50 . The thermal conductivity of the holding frames  80  is, for example, equal to or higher than  80  [W/(m·K)]. It should be noted that the material of the holding frames  80  is not particularly limited, and can also include other metal such as copper. 
     In the present embodiment, the projector  1  is further provided with the cooling promoters  70  respectively provided to the light modulation units  4 R,  4 G, and  4 B as the cooling target. The cooling promoters  70  each have the refrigerant holder  71  and the fixation member  72 . The refrigerant holder  71  is formed of a porous member for retaining the refrigerant W. As the material of the refrigerant holder  71 , there can be cited, for example, polypropylene, cotton, and porous metal. The material of the refrigerant holder  71  can be made the same as the material of, for example, the refrigerant sender  50 . It is preferable for the material of the refrigerant holder  71  to be a material capable of making the surface tension of the refrigerant holder  71  relatively high. 
     The refrigerant holder  71  is disposed on a surface of the extending part  82  as the cooling target part. In the present embodiment, the refrigerant holder  71  is disposed so as to straddle the surfaces on the both sides of the extending part  82  in the direction in which the light passes through each of the light modulators  4 RP,  4 GP, and  4 BP.  FIG. 7  is a diagram showing the refrigerant holder  71 . As shown in  FIG. 7 , the refrigerant holder  71 R provided to the light modulation unit  4 R, the refrigerant holder  71 G provided to the light modulation unit  4 G, and the refrigerant holder  71 B provided to the light modulation unit  4 B are the same in shape as each other. The shape of the refrigerant holder  71 G will hereinafter be described as a representative. 
     The refrigerant holder  71 G has a main body part  71   a  and a pair of folded parts  71   d.  As shown in  FIG. 6 , the main body part  71   a  is disposed on a surface on the light incident side (−X side) of the extending part  82 . The main body part  71   a  has a narrow part  71   b  and a wide part  71   c.    
     In the present embodiment, the narrow part  71   b  has a rectangular shape. The narrow part  71   b  is disposed so as to straddle the surface on the light incident side (−X side) of the first part  82   a  and the surface on the light incident side of the second part  82   b  out of the extending part  82 . The narrow part  71   b  covers a central part in the width direction Y out of the surface on the light incident side of the first part  82   a,  and the entire surface on the light incident side of the second part  82   b.    
     In the present embodiment, the wide part  71   c  has a rectangular shape. The wide part  71   c  is contiguous with an upper side of the narrow part  71   b.  The wide part  71   c  projects on both sides in the width direction Y from the narrow part  71   b.  The wide part  71   c  is disposed on a surface on the light incident side (−X side) of the third part  82   c  out of the extending part  82 . The wide part  71   c  covers the entire surface on the light incident side of the third part  82   c.    
     The pair of folded parts  71   d  are respectively disposed in both end parts in the width direction Y in the upper end part of the wide part  71   c.  The pair of folded parts  71   d  are folded back on the light incident side (+X side) passing through the upper side of the extending part  82 . The pair of folded parts  71   d  are each disposed so as to straddle the surface on the upper side of the third part  82   c  and the surface on the light incident side of the third part  82   c  out of the extending part  82 . The pair of folded parts  71   d  each cover the both end parts in the width direction Y out of the surface on the upper side of the third part  82   c,  and the both end parts in the width direction Y out of the surface on the light incident side of the third part  82   c.    
     As shown in  FIG. 7 , the refrigerant holder  71 G provided to the light modulation unit  4 G out of the refrigerant holders  71  provided to the light modulation units  4 R,  4 G, and  4 B is coupled to the refrigerant sender  50 . More particularly, the coupling part  54  of the refrigerant sender  50  is coupled to a lower end part of the wide part  71   c  out of the refrigerant holder  71 G. In contrast, in the refrigerant holder  71 B attached to the light modulation unit  4 B and the refrigerant holder  71 R attached to the light modulation unit  4 R, the coupling part  54  is not coupled. 
     In the present embodiment, on both sides of the refrigerant holder  71 G attached to the light modulation unit  4 G, there are disposed the junction parts  73   a,    73   b  to which the refrigerant holder  71 B attached to the light modulation unit  4 B and the refrigerant holder  71 R attached to the light modulation unit  4 R are respectively joined. The junction parts  73   a,    73   b  are each made of a porous member. 
     The junction part  73   a  joins the refrigerant holder  71 G attached to the light modulation unit  4 G and the refrigerant holder  71 B attached to the light modulation unit  4 B to each other. More particularly, the junction part  73   a  joins the wide part  71   c  of the refrigerant holder  71 G and the wide part  71   c  of the refrigerant holder  71 B to each other. Thus, the refrigerant holder  71 B is coupled to the coupling part  54  of the refrigerant sender  50  via the refrigerant holder  71 G. As shown in  FIG. 6 , the junction part  73   a  is provided with a cover part  74  for covering the junction part  73   a.  The cover part  74  is, for example, a film made of resin. 
     As shown in  FIG. 7 , the junction part  73   b  joins the refrigerant holder  71 G attached to the light modulation unit  4 G and the refrigerant holder  71 R attached to the light modulation unit  4 R to each other. More particularly, the junction part  73   b  joins the wide part  71   c  of the refrigerant holder  71 G and the wide part  71   c  of the refrigerant holder  71 R to each other. Thus, the refrigerant holder  71 R is coupled to the coupling part  54  of the refrigerant sender  50  via the refrigerant holder  71 G. Although not shown in the drawings, the junction part  73   b  is also provided with the cover part  74  similarly to the junction part  73   a.    
     As shown in  FIG. 6 , the fixation member  72  is a member for fixing the refrigerant holder  71 . Since the fixation members  72  respectively provided to the light modulation units  4 R,  4 G, and  4 B have substantially the same shapes, in the following description, the fixation member  72  for fixing the refrigerant holder  71 G provided to the light modulation unit  4 G will be described as a representative. 
     The fixation member  72  is a plate-like member. The fixation member  72  is made of, for example, metal. The fixation member  72  has a frame part  72   a  and attachment parts  72   b,    72   c.  The frame part  72   a  is located on the light incident side (−X side) of the main body part  71   a  in the refrigerant holder  71 . The frame part  72   a  covers the outer edge part of the main body part  71   a.  An outer shape of the frame part  72   a  is substantially the same as an outer shape of the main body part  71   a.    
     The extending part  82 , the main body part  71   a  of the refrigerant holder  71 , and the frame part  72   a  are stacked on one another in the direction (the optical axis direction X) of the light passing through the light modulation unit  4 G. In the following description, the direction in which the extending part  82 , the main body part  71   a  of the refrigerant holder  71 , and the frame part  72   a  are stacked on one another is simply referred to as a “stacking direction.” The fixation member  72  fixes the main body part  71   a  of the refrigerant holder  71  by sandwiching the main body part  71   a  of the refrigerant holder  71  between the frame part  72   a  and the extending part  82  as the cooling target part in the stacking direction (the optical axis direction X). 
     In the present embodiment, at least a part of the refrigerant holder  71  is exposed when viewed from the fixation member  72  side (the light incident side) in the stacking direction. More particularly, apart located on the inner side of the frame part  72   a  out of the main body part  71   a  of the refrigerant holder  71  is exposed when viewed from the fixation member  72  side in the stacking direction. 
     The attachment parts  72   b  are respectively disposed on both end parts in the width direction Y in a lower portion of the frame part  72   a.  The attachment parts  72   c  are respectively disposed on both end parts in the width direction Y in an upper portion of the frame part  72   a.  The attachment parts  72   b,    72   c  each project from the frame part  72   a  toward the light incident side (+X side). The attachment parts  72   b  are respectively engaged with protrusions disposed on the side surfaces of the second part  82   b  out of the holding frame  80 . The attachment parts  72   c  are respectively engaged with protrusions disposed on the side surfaces of the third part  82   c  out of the holding frame  80 . Thus, the fixation member  72  is fixed to the holding frame  80 . A tip part of each of the attachment parts  72   c  is a click part  72   d  which is bent to press the pair of folded parts  71   d  from the light exit side. It should be noted that in  FIG. 6 , there are shown the click parts  72   d  of the fixation member  72  provided to the light modulation unit  4 R. 
     The light modulation unit  4 R has an interconnection  4 RW electrically coupled to the light modulator  4 RP. The light modulation unit  4 G has an interconnection  4 GW electrically coupled to the light modulator  4 GP. The light modulation unit  4 B has an interconnection  4 BW electrically coupled to the light modulator  4 BP. The interconnections  4 RW,  4 GW, and  4 BW each extend in the up-and-down direction Z on the light exit side of the extending part  82 , and are drawn on the upper side of the extending part  82 . The interconnections  4 RW,  4 GW, and  4 BW are each disposed so as to be opposed to an area between the portions provided with the pair of folded parts  71   d  out of the surface on the light exit side of the extending part  82  in each of the holding frames  80 . 
     As shown in  FIG. 8 , the projector  1  is further provided with the dust-proof case  90  which houses at least a part of the cooling target inside.  FIG. 8  is a cross-sectional view showing the light modulation units  4 B,  4 G, the dust-proof case  90 , and a part of the first duct  61  in the present embodiment, and is a VIII-VIII cross-sectional view in  FIG. 6 . 
     As shown in  FIG. 6  and  FIG. 8 , the dust-proof case  90  is shaped like, for example, a rectangular solid box. The dust-proof case  90  has a dust-proof property. The dust-proof case  90  is closed, and is made capable of blocking passage of grit and dust between the inside and the outside of the dust-proof case  90 . 
     It should be noted that in the present specification, the expression of “a certain object has a dust-proof property” includes that the certain object has a property of preventing grit and dust from passing, or a property of substantially preventing grit and dust from passing. The property of substantially preventing grit and dust from passing includes a property capable of blocking 90% or more of the grit and dust which are urged to pass the certain object. 
     As shown in  FIG. 6 , in the present embodiment, the dust-proof case  90  houses the light combining optical system  5 , the light modulators  4 RP,  4 GP, and  4 BP, and the frame main body part  81  for holding the light modulators  4 RP,  4 GP, and  4 BP inside. In other words, the light modulators  4 RP,  4 GP, and  4 BP as the cooling target main body part are disposed inside the dust-proof case  90 . 
     The dust-proof case  90  is provided with through holes  91  through which the holding frames  80  pass. In the present embodiment, the through holes  91  are disposed in a top wall part  90   a  located on the upper side out of the wall parts constituting the dust-proof case  90  having a rectangular solid shape. The through holes  91  each penetrate the top wall part  90   a  in the up-and-down direction Z. The through holes  91  are each, for example, a hole having a rectangular shape. In the present embodiment, there is provided a plurality of the through holes  91 . As the through holes  91 , for example, there are disposed three through holes  91 R,  91 G, and  91 B. 
     The holding frames  80  of the light modulation units  4 R,  4 G, and  4 B are inserted through the three through holes  91 R,  91 G, and  91 B, respectively. The extending parts  82  provided to the light modulation units  4 R,  4 G, and  4 B project on the upper side of the dust-proof case  90  via the through holes  91 R,  91 G, and  91 B, respectively. Thus, the extending parts  82  as the cooling target part are disposed outside the dust-proof case  90 . As shown in  FIG. 8 , inside each of the through holes  91 , there is inserted an end part on the upper side of the frame main body part  81  out of the holding frame  80 . 
     In the present embodiment, between the through hole  91  and the holding frame  80 , there is disposed a sealing member  92 . The sealing member  92  seals a gap between an inner side surface of the through hole  91  and an outer side surface of the holding frame  80 . In the present embodiment, the sealing member  92  seals the gap between the inner side surface of the through hole  91  and an outer side surface in an upper end part of the frame main body part  81 . It is preferable to use a relatively soft material as the material of the sealing member  92 . This is because it is possible to make it difficult to apply a stress to the holding frame  80  inserted through the through hole  91 . The sealing member  92  can be, for example, a sponge-like member or a gelled member. 
     On the upper side of the dust-proof case  90 , there is disposed the first flow channel part  61   a  of the first duct  61 . A top wall part  90   a  of the dust-proof case  90  is fitted in a hole part  61   e  provided to a wall part on the lower side of the first flow channel part  61   a.  In  FIG. 8 , the direction in which the first flow channel part  61   a  extends is, for example, the optical axis direction X. In other words, in  FIG. 8 , as an example, there is shown when the rotational axis direction DR and the optical axis direction X are the same as each other. 
     Inside the first flow channel part  61   a,  there are disposed the respective extending parts  82  in the plurality of light modulation units  4 R,  4 G, and  4 B, and the cooling promotion parts  70  provided to the respective extending parts  82 . In other words, the extending parts  82  as the cooling target part are disposed inside the first duct  61  in the outside of the dust-proof case  90 . In the present embodiment, inside the first flow channel part  61   a,  the air AR 1  from the first blower  60  flows from the light incident side (−X side) in the optical axis direction X of the light combining optical system  5  toward the light exit side (+X side). The air AR 1  flowing inside the first flow channel part  61   a  is made to blow against the plurality of extending parts  82  and the plurality of cooling promotion parts  70 . Thus, the first blower  60  feeds the air AR 1  to the extending parts  82  as the cooling target part. 
     The refrigerant W generated by the refrigerant generator  20  is transmitted to the refrigerant holder  71 G using the coupling part  54  of the refrigerant sender  50 . The refrigerant W transmitted to the refrigerant holder  71 G is transmitted to the refrigerant holder  71 B via the junction part  73   a,  and at the same time, transmitted to the refrigerant holder  71 R via the junction part  73   b.  In such a manner, the refrigerant W generated in the refrigerant generator  20  is transmitted to the three light modulation units  4 R,  4 G, and  4 B. Then, the refrigerant W transmitted to and then retained in the refrigerant holder  71  is evaporated, and thus, the light modulation units  4 R,  4 G, and  4 B as the cooling target are cooled. More particularly, by the refrigerant W retained in the refrigerant holders  71  evaporating, the extending parts  82  as the cooling target part are cooled, and thus, the frame main body part  81  and the light modulators  4 RP,  4 GP, and  4 BP thermally coupled to the extending parts via the frame main body parts  81  are cooled. Thus, it is possible to cool the light modulation units  4 R,  4 G, and  4 B as the cooling target due to the cooloer  10 . 
     As described above, in the present embodiment, the refrigerant W evaporates in the plurality of extending parts  82  and the plurality of cooling promotion parts  70  housed inside the first flow channel part  61   a.  Therefore, the refrigerant W having evaporated is included in the air AR 1  which has passed the plurality of extending parts  82  and the plurality of cooling promotion parts  70  out of the air AR 1  passing inside the first duct  61 . In the following description, the air AR 1  including the refrigerant W having evaporated in the extending parts  82  is referred to as air AR 4  in some cases. 
     In the present embodiment, the air AR 4  is air which has been fed to the cooling target from the first blower  60  as the cooling blower. As shown in  FIG. 3 , the air AR 4  flows from the first flow channel part  61   a  through the second flow channel part  61   b,  the third flow channel part  61   c,  and the fourth flow channel part  61   d  in this order, and then merges with the air AR 1  flowing inside the second duct  62  in the refrigerant generator  20 . In such a manner, the first duct  61  makes the air AR 4  including the refrigerant W changed in phase to the gas in the cooling target flow toward the refrigerant generator  20 . The air AR 4  having flowed into the second duct  62  from the first duct  61  is fed to the part of the moisture absorption/desorption member  40  located in the first area F 1 . In other words, in the present embodiment, the first duct  61  makes the air AR 4  which has been fed from the first blower  60  as the cooling blower to the cooling target flow toward the moisture absorption/desorption member  40 . 
     It should be noted that in the present specification, the sentence “the first duct makes the air flow toward the moisture absorption/desorption member” is sufficiently satisfied when the air flowing inside the first duct is fed to the moisture absorption/desorption member, and the air AR 4  flowing inside the first duct  61  can be fed to the moisture absorption/desorption member  40  via the second duct  62 , or the air AR 4  discharged from the first duct  61  can be fed to the moisture absorption/desorption member  40  without passing through other ducts. 
     According to the present embodiment, it is possible for the cooloer  10  to cool the cooling target by drawing heat from the cooling target using the evaporation of the refrigerant W as an endothermic reaction after transmitting the refrigerant W generated in the refrigerant generator  20  to the cooling target with the refrigerant sender  50 . The cooling action by the evaporation of the refrigerant W can actively draw heat from the cooling target, and is therefore superior in cooling performance compared to when cooling the cooling target by mere heat transmission to the refrigerant as in the case of air cooling or liquid cooling. Thus, when obtaining the same cooling performance as those of air cooling and liquid cooling, it is easy to reduce the whole of the cooloer  10  in size compared to air cooling and liquid cooling. 
     Further, in the case of the cooling action by the evaporation of the refrigerant W, the cooling performance can be improved by increasing the surface area where the refrigerant W to be evaporated has contact with the cooling target. Therefore, even when raising the cooling performance obtained using the cooloer  10 , it is possible to suppress an increase in the sound noise. As described above, according to the present embodiment, it is possible to obtain the projector  1  equipped with the cooloer  10  excellent in cooling performance, small in size, and excellent in quietness. 
     Further, according to the present embodiment, since the refrigerant W can be generated in the refrigerant generator  20 , time and effort for refilling the refrigerant W are not required for the user, and thus, the convenience of the user can be enhanced. Further, since it is possible for the refrigerant generator  20  to control generation of the refrigerant W so as to generate necessary amount of refrigerant W when needed, it is not necessary to retain the refrigerant W in a reservoir tank or the like, and thus, it is possible to reduce the weight of the projector  1 . 
     Further, according to the present embodiment, there is provided the first duct  61  for making the air AR 4  including the refrigerant W having evaporated in the cooling target flow toward the refrigerant generator  20  for generating the refrigerant W from the air. Therefore, it is possible to feed the refrigerant W having evaporated to the refrigerant generator  20  to generate the refrigerant W by condensing the refrigerant W once again from the air. In other words, it is possible to reuse the refrigerant W having evaporated. Therefore, it is possible to enhance the generation efficiency of the refrigerant W in the refrigerant generator  20 . 
     Further, according to the present embodiment, the cooloer  10  includes the first blower  60  as the cooling blower for feeding the air to the cooling target. Therefore, it is easy to evaporate the refrigerant W transmitted to the light modulation units  4 R,  4 G, and  4 B as the cooling target with the air AR 1  fed from the first blower  60 , and it is possible to further cool the light modulation units  4 R,  4 G, and  4 B. In the present embodiment, since the first blower  60  feeds the air AR 1  to the extending parts  82  as the cooling target part, it is possible to evaporate the refrigerant W transmitted to the extending parts  82  in good condition. 
     Further, according to the present embodiment, the first duct  61  makes the air AR 1  which has been fed from the first blower  60  as the cooling blower to the cooling target flow toward the refrigerant generator  20 . Therefore, it is easy to make the refrigerant W having evaporated in the cooling target flow inside the first duct  61  with the air AR 1  fed from the first blower  60 . Thus, it is possible to feed the refrigerant W having evaporated to the refrigerant generator  20  in good condition. Therefore, it is possible to further enhance the generation efficiency of the refrigerant W in the refrigerant generator  20 . 
     Further, according to the present embodiment, it is possible to absorb the steam included in the air AR 1  fed from the first blower  60  by the moisture absorption/desorption member  40 , and it is possible to release the moisture absorbed by the moisture absorption/desorption member  40  in the air AR 2  fed by the second blower  23  as steam. Further, it is possible to generate the refrigerant W by condensing the moisture released as steam in the air AR 2  using the heat exchanger  30 . Thus, according to the present embodiment, it is possible to generate the refrigerant W from the air in the projector  1 . 
     Further, according to the present embodiment, the first duct  61  makes the air AR 4  which has been fed to the cooling target flow toward the moisture absorption/desorption member  40 . Therefore, it is possible to make the moisture absorption/desorption member  40  absorb once again the refrigerant W which has evaporated and is included in the air AR 4 . Thus, it is easy to make the amount of the steam absorbed by the moisture absorption/desorption member  40  sufficiently large even when, for example, the humidity of the air AR 1  taken in from the outside of the projector  1  by the first blower  60  is relatively low. Therefore, it is possible to further enhance the generation efficiency of the refrigerant W in the refrigerant generator  20 . 
     Further, according to the present embodiment, the refrigerant generator  20  has the second duct  62  which makes the air AR 1  fed from the first blower  60  flow toward the moisture absorption/desorption member  40 . Therefore, it is easy to feed the air AR 1  discharged from the first blower  60  to the moisture absorption/desorption member  40 . Thus, it is possible to make the moisture absorption/desorption member  40  absorb the steam in good condition. Therefore, it is possible to further enhance the generation efficiency of the refrigerant W in the refrigerant generator  20 . 
     Further, according to the present embodiment, the end part on downstream of the first duct  61  in the flow direction of the air AR 1  flowing inside the first duct  61  is coupled to the second duct  62 . Therefore, it is possible to feed the air AR 1  (the air AR 4 ) flowing inside the first duct  61  to the moisture absorption/desorption member  40  in good condition via the second duct  62 . Therefore, it is possible to make the moisture absorption/desorption member  40  absorb the refrigerant W having evaporated in the cooling target once again in good condition, and thus, it is possible to further enhance the generation efficiency of the refrigerant W in the refrigerant generator  20 . 
     Further, according to the present embodiment, the first blower  60  is the cooling blower, and feeds the air AR 1  which has passed through the part of the moisture absorption/desorption member  40  located in the first area F 1  to the cooling target. Therefore, the first blower  60  for feeding the air AR 1  to the moisture absorption/desorption member  40  can be used as the cooling blower. Thus, it is unnecessary to separately provide the cooling blower in addition to the first blower  60 . Therefore, it is possible to prevent the number of components of the projector  1  from increasing, and thus, it is possible to prevent the sound noise from increasing. 
     Further, when the refrigerant W having transmitted to the cooling target evaporates, the humidity of the ambient air becomes relatively high due to the refrigerant W having evaporated. Therefore, there is a possibility that the air relatively high in humidity affects the cooling target to cause a problem. Specifically, when the cooling target is an optical element, there is a possibility that the propagation of the light entering the optical element or the light emitted from the optical element is hindered by the refrigerant W evaporated in the cooling target. Thus, there is a possibility that the reliability of the projector degrades. 
     In contrast, according to the present embodiment, the extending parts  82  as the cooling target part are disposed outside the dust-proof case  90 . Therefore, the refrigerant W transmitted to the extending parts  82  evaporates outside the dust-proof case  90 . On the other hand, the light modulators  4 RP,  4 GP, and  4 BP as the cooling target main body part are disposed inside the dust-proof case  90 . Therefore, it is possible for the dust-proof case  90  to prevent the refrigerant W evaporated outside the dust-proof case  90  from moving to the periphery of the light modulators  4 RP,  4 GP, and  4 BP. Thus, it is possible to prevent the ambient air of the light modulators  4 RP,  4 GP, and  4 BP from becoming high in humidity due to the refrigerant W having evaporated. Therefore, it is possible to prevent the propagation of the light entering the light modulators  4 RP,  4 GP, and  4 BP and the light emitted from the light modulators  4 RP,  4 GP, and  4 BP from being hindered. As described above, according to the present embodiment, it is possible to prevent the refrigerant W having evaporated from causing the problem in the cooling target main body part, and thus, it is possible to enhance the reliability of the projector  1 . 
     In particular, according to the present embodiment, the light modulation units  4 R,  4 G, and  4 B are each the cooling target, and the light modulators  4 RP,  4 GP, and  4 BP are each the cooling target main body part. Therefore, it is possible to prevent the problem from occurring in the light modulators  4 RP,  4 GP, and  4 BP, thus it is possible to prevent the problem that a fluctuation occurs in the color image (picture) emitted from the projector  1 . 
     Further, according to the present embodiment, the extending parts  82  as the cooling target part are disposed inside the first duct  61  in the outside of the dust-proof case  90 , and in the first duct  61 , there inflows the air AR 1  from the first blower  60  as the cooling blower. Therefore, the air AR 1  fed from the first blower  60  can be fed to the plurality of extending parts  82  in good condition. Thus, it is possible to promote the evaporation of the refrigerant W in each of the extending parts  82  in good condition, and thus, it is possible to further cool the light modulation units  4 R,  4 G, and  4 B as the cooling target. Further, since the refrigerant W evaporates inside the first duct  61 , it is possible to feed the refrigerant W having evaporated to the refrigerant generator  20  in good condition with the first duct  61 . 
     Further, according to the present embodiment, the dust-proof case  90  is provided with the through holes  91  through which the holding frames  80  are inserted, and the sealing member  92  is disposed between the through hole  91  and the holding frame  80 . Therefore, it is possible to prevent the foreign matter and the refrigerant W having evaporated from entering the dust-proof case  90  from the gap between the through hole  91  and the holding frame  80 . Thus, the reliability of the projector  1  can further be enhanced. 
     Further, as described above, in the present embodiment, the evaporation of the refrigerant W fed to the cooling target part is promoted using the first blower  60  as the intake fan for taking in the external air inside the projector  1 . Therefore, even when lowering the output of the first blower  60 , it is possible to obtain the cooling performance equivalent to when the cooloer  10  according to the present embodiment is not provided, and the cooling target is cooled only by feeding air. Therefore, it is possible to lower the output of the first blower  60  as the intake fan to thereby reduce the sound noise generated from the first blower  60 , and thus, it is possible to further enhance the quietness of the projector  1 . 
     Further, according to the present embodiment, the holding frames  80  for holding the light modulators  4 RP,  4 GP, and  4 BP as the cooling target main body part are each made of metal. Therefore, the heat of the light modulators  4 RP,  4 GP, and  4 BP is easily transferred to the holding frames  80 . Thus, by cooling the extending parts  82  as the cooling target part out of the holding frames  80  using the evaporation of the refrigerant W, it is possible to cool the light modulators  4 RP,  4 GP, and  4 BP as the cooling target main body part in better condition. 
     Further, according to the present embodiment, the material of the holding frames  80  includes aluminum. Therefore, it is easy to make the thermal conductivity of the holding frames  80  relatively high. Thus, the heat of the light modulators  4 RP,  4 GP, and  4 BP is more easily transferred to the holding frames  80 . Therefore, by cooling the extending parts  82  as the cooling target part out of the holding frames  80  using the evaporation of the refrigerant W, it is possible to cool the light modulators  4 RP,  4 GP, and  4 BP as the cooling target main body part in better condition. 
     Further, according to the present embodiment, the thermal conductivity of the holding frames  80  is higher than the thermal conductivity of the refrigerant sender  50 . Therefore, it is easy to make the thermal conductivity of the holding frames  80  relatively high. Thus, the heat of the light modulators  4 RP,  4 GP, and  4 BP is more easily transferred to the holding frames  80 . Therefore, by cooling the extending parts  82  as the cooling target part out of the holding frames  80  using the evaporation of the refrigerant W, it is possible to cool the light modulators  4 RP,  4 GP, and  4 BP as the cooling target main body part in better condition. 
     Further, according to the present embodiment, the extending parts  82  as the cooling target part are provided with the refrigerant holders  71  for retaining the refrigerant W. Therefore, it is possible to retain the refrigerant W having been transmitted to the extending parts  82  to the extending parts  82  with the refrigerant holders  71  until the refrigerant W evaporates. Thus, it is easy to use the refrigerant W thus generated without a waste, and it is possible to further improve the cooling performance of the cooloer  10 . 
     Further, according to the present embodiment, the refrigerant holders  71  are respectively attached to the surfaces of the extending parts  82  as the cooling target part, and are made of the porous material. Further, at least a part of each of the refrigerant holders  71  is exposed when viewed from the refrigerant holder  71  side in the stacking direction. 
     Therefore, it is easy to evaporate the refrigerant W from the exposed part of the refrigerant holder  71 , and it is possible to further improve the cooling performance of the cooloer  10 . Further, since the refrigerant holders  71  are each made of the porous material, it is easy to make the refrigerant W evenly take over the surface of the cooling target part on which the refrigerant holder  71  is disposed due to the capillary action, and it is easier to cool the cooling target. 
     Further, for example, when fixing the refrigerant holders  71  to the extending parts  82  with an adhesive, the adhesive is absorbed by the refrigerant holders  71  to block the holes of the refrigerant holders  71  made of the porous material in some cases. Therefore, it becomes difficult for the refrigerant W to be absorbed by the refrigerant holders  71 , and it becomes difficult for the refrigerant holders  71  to retain the refrigerant W in some cases. 
     In contrast, according to the present embodiment, there are provided the fixation members  72  each for sandwiching the refrigerant holder  71  with the extending parts  82  to fix the refrigerant holder  71 . Therefore, it is possible to fix the refrigerant holders  71  to the respective extending parts  82  without using the adhesive. Thus, it is possible to prevent the refrigerant holders  71  from becoming difficult to retain the refrigerant W. Further, in the present embodiment, the fixation members  72  are made of metal. Therefore, the fixation members  72  are relatively high in thermal conductivity, and are easy to cool. Therefore, it is easy for the temperature of the fixation members  72  to drop due to the air AR 1  from the first blower  60  and the evaporation of the refrigerant W, and thus, it is easier to cool the cooling target part having contact with the fixation members  72 . 
     Further, according to the present embodiment, the refrigerant holders  71  are provided to the respective light modulation units  4 R,  4 G, and  4 B thus disposed as the plurality of units, and there are provided the junction part  73   a  for joining the two refrigerant holders  71 G,  71 B to each other, and the junction part  73   b  for joining the two refrigerant holders  71 G,  71 R to each other. Therefore, by coupling the refrigerant sender  50  to one of the refrigerant holders  71 , it is possible to transmit the refrigerant W also to the rest of the refrigerant holders  71 . Thus, it is possible to simplify the arrangement of the refrigerant sender  50  inside the projector  1 . 
     Further, according to the present embodiment, the junction parts  73   a,    73   b  are provided with the covering parts  74  for respectively covering the junction parts  73   a,    73   b.  Therefore, it is possible to prevent the refrigerant W moving along the junction parts  73   a,    73   b  from evaporating in the junction parts  73   a,    73   b.  Thus, it is possible to prevent the refrigerant W from evaporating without making a contribution to cooling of the light modulation units  4 R,  4 G, and  4 B as the cooling target, and thus, it is possible to prevent the refrigerant W thus generated from being wasted. 
     It should be noted that in the present embodiment, the coupling part  54  can be coated similarly to the junction parts  73   a,    73   b.  According to this configuration, it is possible to prevent the refrigerant W from evaporating during the transmission to the cooling target. Therefore, it is possible to efficiently transmit the refrigerant W to the cooling target, and at the same time, it is possible to more strictly prevent the refrigerant W thus generated from being wasted. It is also possible for the coupling part  54  and the junction parts  73   a,    73   b  to be coated in the periphery with, for example, a tube. Further, it is also possible for the coupling part  54  and the junction parts  73   a,    73   b  to be provided with a coating treatment for preventing the evaporation on the respective surfaces. 
     Further, for example, in the refrigerant generator  20 , when the humidity of the air AR 2  fed from the second blower  23  to the heat exchanger  30  is relatively low, the refrigerant W is difficult to be generated in some cases even when the heat exchanger  30  is cooled. The humidity of the air AR 2  to be fed to the heat exchanger  30  drops in some cases when, for example, the air outside the projector  1  is mixed with the air AR 2 . 
     In this regard, according to the present embodiment, the refrigerant generator  20  has the circulation channel  27  through which the air AR 2  discharged from the second blower  23  circulates. Therefore, it is possible to prevent the air located outside the projector  1  from entering the circulation channel  27  by substantially sealing the circulation channel  27 , and it is easy to keep the humidity of the air AR 2  fed to the heat exchanger  30  in a relatively high state. Therefore, by cooling the heat exchanger  30 , it is possible to generate the refrigerant W in good condition. 
     Further, according to the present embodiment, the heater  22  has the heating main body part  22   a  for heating the air which has not passed the part of the moisture absorption/desorption member  40  located in the second area F 2 , and the second blower  23 . Therefore, it is possible for the heater  22  to heat the part of the moisture absorption/desorption member  40  located in the second area F 2  by feeding the air AR 2  to the moisture absorption/desorption member  40  using the second blower  23 . Thus, it is possible to heat the moisture absorption/desorption member  40  using the heater  22  even when disposing the heating main body part  22   a  at a position distant from the moisture absorption/desorption member  40 . Therefore, the degree of freedom of the configuration of the heater  22  can be enhanced. 
     Further, according to the present embodiment, the refrigerant generator  20  has the motor  24  for rotating the moisture absorption/desorption member  40 . Therefore, it is possible to stably rotate the moisture absorption/desorption member  40  at a constant speed. Thus, it is possible to make the part of the moisture absorption/desorption member  40  located in the first area F 1  preferably absorb the steam from the air AR 1 , and at the same time, it is possible to make the part of the moisture absorption/desorption member  40  located in the second area F 2  preferably release the moisture to the air AR 2 . Therefore, it is possible to efficiently generate the refrigerant W. 
     Further, according to the present embodiment, the refrigerant sender  50  transmits the refrigerant W due to a capillary action. Therefore, there is no need to separately prepare a power source such as a pump for transmitting the refrigerant W. Thus, it is possible to prevent the number of components of the projector  1  from increasing, and thus, it is easier to reduce the size and the weight of the projector  1 . 
     Further, according to the present embodiment, the refrigerant sender  50  has the coupling part  54  made of the porous material for coupling the refrigerant generator  20  and the cooling target to each other. Therefore, it is possible to make the coupling part  54  absorb the refrigerant W to transmit the refrigerant W with the capillary action. 
     Further, according to the present embodiment, the refrigerant sender  50  has the second trapping part  52  disposed inside the second lid part  33 . The second trapping part  52  is coupled to the coupling part  54 . Therefore, it is possible to absorb the refrigerant W retained inside the second lid part  33  using the second trapping part  52  to transmit the refrigerant W to the coupling part  54  using the capillary action. Thus, it is easy to transmit the refrigerant W thus generated to the cooling target without a waste. 
     Further, according to the present embodiment, the refrigerant sender  50  has the first trapping part  51  disposed inside the first lid part  32 , and a third trapping part  53  for coupling the first trapping part  51  and the second trapping part  52  to each other. Thus, it is possible to absorb the refrigerant W retained inside the first lid part  32  using the first trapping part  51  to transmit the refrigerant W to the second trapping part  52  via the third trapping part  53  using the capillary action. Therefore, it is possible to transmit the refrigerant W retained inside the first lid part  32  from the second trapping part  52  to the coupling part  54  to transmit the refrigerant W to the cooling target. Therefore, it is easy to transmit the refrigerant W thus generated to the cooling target with a fewer waste. 
     Further, according to the present embodiment, the third trapping part  53  passes through the pipe part  31   a.  Therefore, it is possible to absorb the refrigerant W retained inside the pipe part  31   a  using the third trapping part  53  to transmit the refrigerant W to the cooling target via the second trapping part  52  and the coupling part  54 . Therefore, it is easy to transmit the refrigerant W thus generated to the cooling target with a fewer waste. 
     Further, according to the present embodiment, the width of the coupling part  54  is larger than, for example, the width of the first trapping part  51 , the width of the second trapping part  52 , and the width of the third trapping part  53 . Therefore, it is easy to make the width of the coupling section  54  relatively large, and it is possible to increase the amount of the refrigerant W which can be transmitted by the coupling part  54 . Therefore, it is easy to transmit the refrigerant W to the cooling target using the refrigerant sender  50 , and it is easier to cool the cooling target. 
     Further, on the other hand, it is easy to make the width of the first trapping part  51 , the width of the second trapping part  52 , and the width of the third trapping part  53  relatively small. Therefore, it is possible to reduce the amount of the refrigerant W to be retained by the first trapping part  51 , the second trapping part  52 , and the third trapping part  53 . Thus, it is possible to reduce the amount of the refrigerant W remaining inside the heat exchanger  30  while being retained in the first trapping part  51 , the second trapping part  52 , and the third trapping part  53 , and it is easy to transmit the refrigerant W thus generated to the cooling target with a fewer waste. 
     Second Embodiment 
     The present embodiment is different in configuration of the first duct  161  from the first embodiment.  FIG. 9  is a schematic configuration diagram schematically showing a part of a cooloer  110  in the present embodiment. It should be noted that the constituents substantially the same as those of the embodiment described above are arbitrarily denoted by the same reference symbols, and the description thereof will be omitted in some cases. 
     As shown in  FIG. 9 , in the cooloer  110  in the present embodiment, a second duct  162  of a refrigerant generator  120  is not coupled to a first duct  161 . The rest of the configuration of the second duct  162  is substantially the same as the rest of the configuration of the second duct  62  in the first embodiment. The rest of the configuration of the refrigerant generator  120  is substantially the same as the rest of the configuration of the refrigerant generator  20  in the first embodiment. 
     The first duct  161  includes the first flow channel part  61   a,  the second flow channel part  61   b,  the third flow channel part  61   c,  a fourth flow channel part  161   d,  and a fifth flow channel part  161   f.  Unlike the fourth flow channel part  61   d  in the first embodiment, the fourth flow channel part  161   d  is not coupled to the second duct  162 . The rest of the configuration of the fourth flow channel part  161   d  is substantially the same as the rest of the configuration of the fourth flow channel part  61   d  in the first embodiment. 
     The fifth flow channel part  161   f  extends from an end part on the other side (−DE side) in the extension direction DE in the fourth flow channel part  161   d  toward the one side (+DR side) in the rotational axis direction DR. The fifth flow channel part  161   f  is located on the other side (−DR side) in the rotational axis direction DR in the moisture absorption/desorption member  40 . An end part on the one side in the rotational axis direction DR in the fifth flow channel part  161   f  opens, and is opposed to the part of the moisture absorption/desorption member  40  located in the first area F 1  with a gap. 
     In the present embodiment, the air AR 1  having flowed into the first duct  161  from the first blower  60  via the moisture absorption/desorption member  40  flows the first flow channel part  61   a,  the second flow channel part  61   b,  the third flow channel part  61   c,  the fourth flow channel part  161   d,  and the fifth flow channel part  161   f  in this order, and is then released toward the moisture absorption/desorption member  40 . In other words, in the present embodiment, an end part on the one side (+DR side) in the rotational axis direction DR in the fifth flow channel part  161   f  corresponds to an end part at downstream of the first duct  161  in the flow direction of the air AR 1  flowing inside the first duct  161 . 
     The air AR 1  (the air AR 4 ) released toward the moisture absorption/desorption member  40  from the first duct  161  passes the moisture absorption/desorption member  40  to inflow inside the first duct  161  once again from the first flow channel part  61   a.  The air AR 1  (the air AR 4 ) which has been released from the first duct  161  and then flowed into the first duct  161  once again merges with the air AR 1  fed from the second duct  162  in the first flow channel part  61   a.    
     The rest of the configuration of the first duct  161  is substantially the same as the rest of the configuration of the first duct  61  in the first embodiment. The rest of the configuration of the cooloer  110  is substantially the same as the rest of the configuration of the cooloer  10  in the first embodiment. 
     According to the present embodiment, similarly to the first embodiment, the first duct  161  makes the air AR 4  which has been fed to the cooling target flow toward the moisture absorption/desorption member  40 . Therefore, it is possible to make the moisture absorption/desorption member  40  absorb once again the refrigerant W which has evaporated and is included in the air AR 4 . Thus, it is possible to increase the amount of the steam to be absorbed by the moisture absorption/desorption member  40 . Therefore, it is possible to enhance the generation efficiency of the refrigerant W in the refrigerant generator  120 . 
     Third Embodiment 
     The present embodiment is different in shape of a first flow channel part  261   a  in a first duct  261  from the first embodiment. The rest of the configuration in the present embodiment is substantially the same as the rest of the configuration in the first embodiment.  FIG. 10  is a cross-sectional view of the light modulation units  4 R,  4 G, and  4 B and a part of the first duct  261  viewed from the upper side. It should be noted that the constituents substantially the same as those of the embodiment described above are arbitrarily denoted by the same reference symbols, and the description thereof will be omitted in some cases. 
     As shown in  FIG. 10 , the first flow channel part  261   a  extends so as to form an angulated U-shape when viewed from the upper side. The first flow channel part  261   a  has a first circulation part  261   g,  a second circulation part  261   h,  and a third circulation part  261   i.  The first circulation part  261   g  and the third circulation part  261   i  extend in the optical axis direction X, and are arranged at a distance in the width direction Y. The second circulation part  261   h  extends in the width direction Y to join an end part of the first circulation part  261   g  and an end part of the third circulation part  261   i  to each other. 
     Inside the first circulation part  261   g,  there is disposed the extending part  82  of the light modulation unit  4 R. Inside the second circulation part  261   h,  there is disposed the extending part  82  of the light modulation unit  4 G. Inside the third circulation part  261   i,  there is disposed the extending part  82  of the light modulation unit  4 B. 
     Evaporation surfaces  82   d,    82   e  provided with the refrigerant holder  71  out of the extending part  82  of the light modulation unit  4 R are disposed along the optical axis direction X in which the first circulation part  261   g  extends. Evaporation surfaces  82   d,    82   e  provided with the refrigerant holder  71  out of the extending part  82  of the light modulation unit  4 G are disposed along the width direction Y in which the second circulation part  261   h  extends. Evaporation surfaces  82   d,    82   e  provided with the refrigerant holder  71  out of the extending part  82  of the light modulation unit  4 B are disposed along the optical axis direction X in which the third circulation part  261   i  extends. In each of the extending parts  82 , the evaporation surface  82   d  is a surface facing to the light incident side in the direction of the light passing through each of the light modulation units  4 R,  4 G, and  4 B. In each of the extending parts  82 , the evaporation surface  82   e  is a surface facing to the light exit side in the direction of the light passing through each of the light modulation units  4 R,  4 G, and  4 B. 
     In the inside of the first flow channel part  261   a,  the air AR 1  flows inside the first circulation part  261   g,  inside the second circulation part  261   h,  and inside the circulation part  261   i  in this order. In other words, the extending parts  82  of the respective light modulation units  4 R,  4 G, and  4 B are arranged along the flow direction of the air AR 1  flowing inside the first flow channel part  261   a.  The air AR 1  flowing inside the first flow channel part  261   a  is fed to the extending part  82  of the light modulation unit  4 R, the extending part  82  of the light modulation unit  4 G, and the extending part  82  of the light modulation unit  4 B in this order. 
     As described above, according to the present embodiment, it is possible to feed the air AR 1  from the first blower  60  in sequence to the plurality of extending parts  82 . Therefore, it is easy to feed the air AR 1  in good condition to each of the extending parts  82 . Specifically, for example, by disposing the evaporation surfaces  82   d,    82   e  disposed on the respective sides opposite to each other along the direction in which the first flow channel part  261   a  extends, it is possible to make it easy to make the air AR 1  have contact with both of the evaporation surface  82   d  and the evaporation surface  82   e.  Thus, it is possible to make it easy to feed the air AR 1  to the refrigerant holder  71  disposed on the evaporation surfaces  82   d,    82   e  of the extending part  82 , and thus, it is possible to efficiently evaporate the refrigerant W having been transmitted to the refrigerant holder  71 . Therefore, it is possible to promote the evaporation of the refrigerant W in each of the extending parts  82  in good condition, and thus, it is easier to cool the light modulation units  4 R,  4 G, and  4 B as the cooling target. 
     Fourth Embodiment 
     The present embodiment is different in shape of a first flow channel part  361   a  in a first duct  361  from the first embodiment. The rest of the configuration in the present embodiment is substantially the same as the rest of the configuration in the first embodiment.  FIG. 11  is a cross-sectional view of the light modulation units  4 R,  4 G, and  4 B and a part of the first duct  361  viewed from the upper side. It should be noted that the constituents substantially the same as those of the embodiment described above are arbitrarily denoted by the same reference symbols, and the description thereof will be omitted in some cases. 
     As shown in  FIG. 11 , the first flow channel part  361   a  includes an inflow part  363   f,  a first circulation part (a branch path)  363   a,  and a second circulation part (a branch path)  363   b.  The inflow part  363   f  is a portion where the air AR 1  from the first blower  60  inflows. The inflow part  363   f  extends in the optical axis direction X. In the inflow part  363   f,  the air AR 1  inflows from the other side (−X side) in the optical axis direction X toward the one side (+X side). 
     The first circulation part  363   a  and the second circulation part  363   b  correspond to a plurality of branch paths to which the air AR 1  fed from the first blower  60  via the inflow part  363   f  branches. The first circulation part  363   a  extends from the inflow part  363   f  toward the other side (−Y side) in the width direction Y. The second circulation part  363   b  extends from the inflow part  363   f  toward the one side (+X side) in the optical axis direction X, and is then folded back to form an angulated U-shape to join the first circulation part  363   a.  The second circulation part  363   b  includes an upstream part  363   c,  a midstream part  363   d,  and a downstream. part  363   e.    
     The upstream. part  363   c  and the downstream. part  363   e  extend in the optical axis direction X, and are arranged at a distance in the width direction Y. The midstream part  363   d  extends in the width direction Y to join an end part on the one side (+X side) in the optical axis direction of the upstream part  363   c  and an end part on the one side in the optical axis direction of the downstream part  363   e  to each other. An end part on the other side (−X side) in the optical axis direction of the downstream part  363   e  joins the first circulation part  363   a.    
     The air AR 1  having flowed inside the first flow channel part  361   a  from the inflow part  363   f  branches into air ARla inflowing into the first circulation part  363   a,  and air ARlb inflowing into the second circulation part  363   b.  The air ARlb inflowing into the second circulation part  363   b  flows through the upstream part  363   c,  the midstream part  363   d,  and the downstream part  363   e  in this order, and then joins the air AR 1   a  flowing inside the first circulation part  363   a.    
     Inside the first circulation part  363   a,  there is disposed the extending part  82  of the light modulation unit  4 G. Inside the second circulation part  363   b,  there are disposed the extending part  82  of the light modulation unit  4 R and the extending part  82  of the light modulation unit  4 B. In other words, in each of the first circulation part  363   a  and the second circulation part  363   b  as the plurality of branch paths, there is disposed at least one extending part  82 . In the present embodiment, the extending part  82  of the light modulation unit  4 R is disposed inside the upstream part  363   c  out of the second circulation part  363   b.  The extending part  82  of the light modulation unit  4 B is disposed inside the downstream. part  363   e  out of the second circulation part  363   b.  The extending parts  82  of the respective light modulation units  4 R,  4   g,  and  4 B are disposed so that the evaporation surfaces  82   d,    82   e  are arranged along the direction in which each part of the first flow channel part  361   a  extends similarly to the third embodiment. 
     The air ARla inflowing into the first circulation part  363   a  is fed to the extending part  82  of the light modulation unit  4 G. The air ARlb inflowing into the second circulation part  363   b  is fed to the extending part  82  of the light modulation unit  4 R and the extending part  82  of the light modulation unit  4 B in this order. 
     According to the present embodiment, the first flow channel part  361   a  has the first circulation part  363   a  and the second circulation part  363   b  as the plurality of branch paths, and at least one extending part  82  is disposed in each of the circulation parts. Therefore, it is possible to make the air AR 1   a,  AR 1   b  which has not passed through the cooling target part inflow into the respective flowing parts as the branch paths. Thus, it is easy to feed the air AR 1  relatively low in temperature to the plurality of cooling target pars, and thus, it is easier to cool the cooling target. 
     Specifically, in the present embodiment, the air ARla inflowing into the first circulation part  363   a  is fed to the extending part  82  of the light modulation unit  4 G without passing other extending parts  82 . Further, the air ARlb inflowing into the second circulation part  363   b  is fed to the extending part  82  of the light modulation unit  4 R without passing other extending parts  82 . Therefore, it is possible to feed the air AR 1  which has not passed other extending parts  82  and is therefore relatively low in temperature to the extending part  82  of the light modulation unit  4 G and the extending part  82  of the light modulation unit  4 R. 
     Further, the air ARla flowing inside the first circulation part  363   a  is fed only to the extending part  82  of the light modulation unit  4 G out of the plurality of extending parts  82 . Here, the light modulation unit  4 G is apt to be higher in amount of heat generation than the other light modulation units  4 R,  4 B. Therefore, the air ARla which has passed the extending part  82  of the light modulation unit  4 G is apt to become relatively high in temperature. Therefore, by adopting the configuration in which the air ARla passing the extending part  82  of the light modulation unit  4 G is not fed to the other extending parts  82 , the extending parts  82  of the plurality of light modulation units  4 R,  4 G, and  4 B can efficiently be cooled. 
     Fifth Embodiment 
     The present embodiment is different in the point that a circulation blower  495  is disposed from the first embodiment.  FIG. 12  is a cross-sectional view showing the light modulation units  4 B,  4 G, the dust-proof case  490 , and the first duct  61 . It should be noted that the constituents substantially the same as those of the embodiment described above are arbitrarily denoted by the same reference symbols, and the description thereof will be omitted in some cases. 
     The projector  401  according to the present embodiment is provided with a circulation blower  495  housed inside the dust-proof case  490 . The circulation blower  495  circulates the air inside the dust-proof case  490 . In the present embodiment, the direction in which the circulation blower  495  discharges the air is the same direction as the direction in which the air AR 1  flows inside the first flow channel part  61   a.  The circulation blower  495  is, for example, a centrifugal fan. It should be noted that the circulation blower  495  can also be an axial fan. 
     The dust-proof case  490  has a heatsink (a heat dissipation structure)  494 . The heatsink  494  is a heat dissipation structure for releasing the heat outside the dust-proof case  490 . In the present embodiment, the heatsink  494  is disposed in a sidewall part  490   b  located on one side (+X side) in the optical axis direction out of the wall parts of the dust-proof case  490 . In the present embodiment, the heatsink  494  has a base part  494   a,  a plurality of inner fins  494   b,  and a plurality of outer fins  494   c.    
     The base part  494   a  is fitted in a hole part  490   c  provided to the sidewall part  490   b  to constitute a part of the sidewall part  490   b.  The inner side surface of the base part  494   a  constitutes a part of the inner side surface of the dust-proof case  490 . The outer side surface of the base part  494   a  constitutes a part of the outer side surface of the dust-proof case  490 . The plurality of inner fins  494   b  is disposed on the inner side surface of the base part  494   a,  namely the inner side surface of the dust-proof case  490 . The plurality of inner fins  494   b  projects to the inside of the dust-proof case  490  from the base part  494   a.  The plurality of outer fins  494   c  is disposed on the outer side surface of the base part  494   a,  namely the outer side surface of the dust-proof case  490 . The plurality of outer fins  4   94   c  projects to the outside of the dust-proof case  490  from the base part  494   a.    
     The rest of the configuration of the dust-proof case  490  is substantially the same as the rest of the configuration of the dust-proof case  90  in the first embodiment. The rest of the configuration of the projector  401  is substantially the same as the rest of the configuration of the projector  1  according to the first embodiment. 
     According to the present embodiment, the circulation blower  495  is disposed inside the dust-proof case  490 . Therefore, it is possible to circulate the air inside the duct-proof case  490  using the circulation blower  495 . Thus, it is easy to transfer the heat of the light modulators  4 RP,  4 GP, and  4 BP housed inside the dust-proof case  490  to the wall part of the dust-proof case  490  via the air circulating. Therefore, it is possible to make it easy to release the heat of the light modulators  4 RP,  4 GP, and  4 BP to the outside from the wall part of the dust-proof case  490 . Therefore, it is possible to cool the light modulation units  4 R,  4 G, and  4 B as the cooling target. 
     Further, according to the present embodiment, the dust-proof case  490  has the heatsink  494  as the heat dissipation structure for releasing heat outside the dust-proof case  490 . Therefore, it is possible to make it easy to release the heat transferred to the wall part of the dust-proof case  490  from the light modulators  4 RP,  4 GP, and  4 BP via the air located inside the dust-proof case  490  to the outside of the dust-proof case  490  using the heatsink  494 . Thus, it is possible to release the heat of the light modulators  4 RP,  4 GP, and  4 BP to the outside of the dust-proof case  490  in better condition. Therefore, it is possible to cool the light modulation units  4 R,  4 G, and  4 B as the cooling target in better condition. 
     Further, according to the present embodiment, the heatsink  494  has the plurality of inner fins  494   b  disposed on the inner side surface of the dust-proof case  490 . Therefore, it is easy to absorb the heat of the light modulators  4 RP,  4 GP, and  4 BP from the air located inside the dust-proof case  490  via the plurality of inner fins  494   b.  Thus, it is possible to make it easier to release the heat of the light modulators  4 RP,  4 GP, and  4 BP to the outside of the dust-proof case  490 . 
     Further, according to the present embodiment, the heatsink  494  has the plurality of outer fins  494   c  disposed on the outer side surface of the dust-proof case  490 . Therefore, it is easy to release the heat of the light modulators  4 RP,  4 GP, and  4 BP transferred to the heatsink  494  via the air located inside the dust-proof case  490  to the air located outside the dust-proof case  490  via the plurality of outer fins  494   c.  Thus, it is possible to make it easier to release the heat of the light modulators  4 RP,  4 GP, and  4 BP to the outside of the dust-proof case  490 . 
     It should be noted that in the present embodiment, it is also possible to adopt the configurations and methods described below. 
     The cooloer is only required to have the refrigerant generator, the refrigerant sender, and the first duct, but is not required to have, for example, the cooling blower for feeding the air to the cooling target. In this case, it is possible for the cooloer to separately have a blower for feeding the refrigerant having evaporated in the cooling target to the first duct. In this case, it is possible for the blower to feed the air to the upper side in the vertical direction of the cooling target to feed the refrigerant which has evaporated to thereby rise to the upper side in the vertical direction to the first duct. Further, it is possible to adopt a configuration in which the first duct can suction the refrigerant having evaporated. In this case, it is possible to install a fan or the like for suctioning the refrigerant in, for example, the inside of the first duct or the outside on the refrigerant generator side of the first duct. It is not required to dispose the cooling target part inside the first duct. The shape of the first duct is not particularly limited providing the first duct is capable of making the air including the refrigerant having evaporated in the cooling target flow toward the refrigerant generator. It is possible to provide a plurality of the first ducts. 
     The refrigerant generator can have a configuration of, for example, condensing the steam on the heat absorption surface of a Peltier element to thereby generate the refrigerant. In this case, it is possible for the first duct to have the configuration of feeding the refrigerant having evaporated to the periphery of a heat absorption surface of the Peltier element out of the refrigerant generator. 
     The second duct can be eliminated. In this case, it is possible for the first duct to directly feed the air to the moisture absorption/desorption member as in the second embodiment described above, or to merge the air with the air fed from the first blower and then feed the air to the moisture absorption/desorption member. 
     In the embodiments described above, it is assumed that the cooling blower is the first blower  60  provided to the refrigerant generator  20 , but this is not a limitation. The refrigerant blower can also be separately provided in addition to the blowers provided to the refrigerant generator  20 . 
     In the embodiments described above, it is assumed that the cooling target is the light modulation units, but this is not a limitation. The cooling target is not particularly limited, but can be the light modulator, or can also include at least one of the light modulator, the light modulation units, the light source device, a wavelength conversion element for converting the wavelength of the light emitted from the light source device, a diffusion element for diffusing the light emitted from the light source device, and a polarization conversion element for converting the polarization direction of the light emitted from the light source device. According to this configuration, it is possible to cool each of the constituents of the projector in a similar manner as described above. The shape of the cooling target part is not particularly limited. The shape of the dust-proof case is not particularly limited. The dust-proof case can be eliminated. 
     The heater is not limited to the embodiments described above. The heater can have a configuration of having contact with the moisture absorption/desorption member to heat the moisture absorption/desorption member. In this case, the heater is not required to heat the air which has not passed through the moisture absorption/desorption member. 
     Further, although in the embodiments described above, there is described the example when the present disclosure is applied to the transmissive projector, the present disclosure can also be applied to reflective projectors. Here, “transmissive” denotes that the light modulator including the liquid crystal panel and so on is a type of transmitting the light. Further, “reflective” denotes that the light modulator is a type of reflecting the light. It should be noted that the light modulator is not limited to the liquid crystal panel or the like, but can also be a light modulator using, for example, micro-mirrors. 
     Further, although in the embodiments described above, there is cited the example of the projector using the three light modulators, the present disclosure can also be applied to a projector using one light modulator alone or a projector using four or more light modulators. 
     Further, the configurations described in the present specification can arbitrarily be combined with each other within a range in which the configurations do not conflict with each other.