Abstract:
A projector includes a first cooling object and a second cooling object, a first circulatory cooling device having a first closed housing, and adapted to circulate a first cooling gas in the first closed housing to cool the first cooling object disposed in the first closed housing, and a second circulatory cooling device having a second closed housing, and adapted to circulate a second cooling gas in the second closed housing to cool the second cooling object disposed in the second closed housing, the first cooling object is an image forming section including a light modulation device adapted to modulate light entering the light modulation device to form an image, and the second cooling object is a first optical component included in an optical component making a contribution to the formation of the image by the light modulation device.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a projector. 
         [0003]    2. Related Art 
         [0004]    In the past, there has been known a projector provided with a light source device, a light modulation device for modulating the light emitted from the light source device to thereby form an image corresponding to image information, and a projection optical device for projecting the image thus formed on a target projection surface such as a screen in an enlarged manner. As such a projector, there has been proposed a configuration provided with a cooling device for cooling an optical device (including liquid crystal panels as light modulation devices) and a polarization conversion element using the air circulating in an exterior housing (see, e.g., JP-A-2009-86197 (Document 1)). 
         [0005]    The projector described in Document 1 is provided with two sirocco fans and a duct. The cooling air fed from each of the two sirocco fans is divided by the duct, and then supplied to each of cooling objects (the optical device and the polarization conversion elements). 
         [0006]    Incidentally, in the projector described in Document 1, since the plurality of cooling objects (e.g., the optical device and the polarization conversion elements) is not disposed in an closed space, if the projector is used in a dusty environment, there is a possibility that the dust adheres to the optical device and so on to show a shadow in the projected image, and thus the image is deteriorated. To deal with the above, in order to inhibit the dust from adhering to the optical device and so on, it is possible to keep the plurality of cooling objects in a closed housing, and then circulate the cooling air in the closed housing to thereby cool the plurality of cooling objects. 
         [0007]    However, in the case in which the plurality of (e.g., two) cooling objects is kept in the closed housing, there is a problem that the device grows in size due to a heat absorber for absorbing the heat of the cooling air circulating in the closed housing, and in order to release the heat from the heat absorber to the outside of the closed housing. Further, there is a problem that it is difficult to control each of the cooling objects at an appropriate temperature. 
       SUMMARY 
       [0008]    An advantage of some aspects of the invention is to provide a projector, which can be miniaturized. 
         [0009]    A projector according to an aspect of the invention includes a first cooling object and a second cooling object, a first circulatory cooling device having a first closed housing, and adapted to circulate a first cooling gas in the first closed housing to cool the first cooling object disposed in the first closed housing, and a second circulatory cooling device having a second closed housing, and adapted to circulate a second cooling gas in the second closed housing to cool the second cooling object disposed in the second closed housing, the first cooling object is an image forming section including a light modulation device adapted to modulate light entering the light modulation device to form an image, and the second cooling object is a first optical component included in an optical component making a contribution to the formation of the image by the light modulation device. 
         [0010]    According to the aspect of the invention, since the first cooling object and the second cooling object are respectively cooled by the first circulatory cooling device and the second circulatory cooling device separated from each other, it is possible to appropriately cool each of the first cooling object and the second cooling object, and control the first cooling object and the second cooling object at an appropriate temperature. 
         [0011]    Here, in the case in which the first cooling object and the second cooling object are respectively disposed at positions distant from each other, if the first and second cooling objects are cooled with a single circulatory cooling device, the circulatory cooling device grows in size. In contrast, according to this aspect of invention, the first circulatory cooling device and the second circulatory cooling device can be downsized compared to the case of cooling the first cooling object (the image forming section) and the second cooling object with the single circulatory cooling device. Further, by separately disposing the first circulatory cooling device and the second circulatory cooling device, the freedom of arrangement of the first circulatory cooling device and the second circulatory cooling device in the projector is enhanced. Therefore, the projector can be downsized. 
         [0012]    In the aspect of the invention described above, it is preferable that the first optical component is a polarization conversion element. 
         [0013]    According to the aspect of the invention with this configuration, the polarization conversion element can individually be cooled by the second circulatory cooling device. Thus, the temperature of each of the image forming section and the polarization conversion element can appropriately be controlled. 
         [0014]    In the aspect of the invention described above, it is preferable that the first optical component is a wavelength conversion element to be excited by excitation light entering the wavelength conversion element and adapted to emit fluorescent light. 
         [0015]    According to the aspect of the invention with this configuration, the wavelength conversion element can individually be cooled by the second circulatory cooling device. Thus, the temperature of each of the image forming section and the wavelength conversion element can be controlled at more appropriate temperature. 
         [0016]    In the aspect of the invention described above, it is preferable that the first closed housing and the second closed housing are separated by a division wall, and the division wall is constituted by an optical component housing adapted to hold the optical component, and a second optical component included in the optical component. 
         [0017]    According to the aspect of the invention with this configuration, since the division wall is constituted by the optical component housing, and the second optical component, the number of parts can be reduced, and at the same time, downsizing can be achieved compared to the case of constituting the first closed housing and the second closed housing only by other parts. Further, since the first closed housing and the second closed housing are separated from each other by the optical component housing and the second optical component, it is possible to surely cool the first cooling object and the second cooling object, and at the same time control the first cooling object and the second cooling object at an appropriate temperature. 
         [0018]    In the aspect of the invention described above, it is preferable that the second optical component includes a reflecting member adapted to reflect light entering the second optical component. 
         [0019]    It should be noted that as the reflecting member described above, there can be cited a dichroic mirror and so on besides a total reflection mirror. According to the aspect of the invention with this configuration, since the reflecting member constitutes apart of the division wall, the first closed housing and the second closed housing can surely be constituted by the reflecting member. 
         [0020]    In the aspect of the invention described above, it is preferable that the second optical component includes a lens. 
         [0021]    According to the aspect of the invention with this configuration, since the lens constitutes a part of the division wall, the first closed housing and the second closed housing can surely be constituted by the lens. 
         [0022]    In the aspect of the invention described above, it is preferable that the first circulatory cooling device includes a first circulation fan adapted to circulate the first cooling gas in the first closed housing, and a first cooler adapted to cool the first cooling gas circulated, and the second circulatory cooling device includes a second circulation fan adapted to circulate the second cooling gas in the second closed housing, and a second cooler adapted to cool the second cooling gas circulated. 
         [0023]    It should be noted that as the cooler described above, there can be cited a heat exchanger, a heat absorber, and so on. 
         [0024]    In the aspect of the invention described above with this configuration, the first cooling gas and the second cooling gas circulating in the first closed housing and the second closed housing can be cooled by the first heat absorber and the second heat absorber, respectively. Therefore, the first cooling object and the second cooling object can surely be cooled by the first cooling gas and the second cooling gas, respectively. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
           [0026]      FIG. 1  is a schematic perspective view showing a projector according to a first embodiment of the invention. 
           [0027]      FIG. 2  is a schematic diagram showing an internal configuration of the projector according to the first embodiment. 
           [0028]      FIG. 3  is a block diagram of a first circulatory cooling device of the projector according to the first embodiment. 
           [0029]      FIG. 4  is a cross-sectional view showing a flow path of a second circulatory cooling device of the projector according to the first embodiment. 
           [0030]      FIG. 5  is a perspective view of the second circulatory cooling device and an optical component housing of the projector according to the first embodiment viewed from an opposite side to a light emission direction. 
           [0031]      FIG. 6  is a perspective view of the second circulatory cooling device and the optical component housing of the projector according to the first embodiment viewed from a direction different from the direction in  FIG. 5 . 
           [0032]      FIG. 7  is a plan view of the optical component housing of the projector according to the first embodiment. 
           [0033]      FIG. 8  is a perspective view showing a part of the optical component housing of the projector according to the first embodiment in an enlarged manner. 
           [0034]      FIG. 9  is a cross-sectional perspective view of the second circulatory cooling device of the projector according to the first embodiment viewed from the opposite side to the light emission direction. 
           [0035]      FIG. 10  is a cross-sectional perspective view of the second circulatory cooling device of the projector according to the first embodiment viewed from a direction angle from the angle in  FIG. 9 . 
           [0036]      FIG. 11  is a cross-sectional view showing cooling objects and a flow path of a second circularly cooling device of a projector according to a second embodiment of the invention. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     First Embodiment 
       [0037]    A first embodiment of the invention will hereinafter be described with reference to the accompanying drawings. 
       Appearance Configuration of Projector 
       [0038]      FIG. 1  is a schematic perspective view showing a projector  1  according to the present embodiment of the invention. 
         [0039]    The projector  1  according to the present embodiment is a projection display device for modulating the light emitted from an illumination device  31  described later to thereby form an image corresponding to image information, and then projecting the image on a projection target surface such as a screen in an enlarged manner. 
         [0040]    Although described later in detail, the projector  1  is provided with a first cooling object and a second cooling object each disposed inside a closed housing, and has a function of circulating cooling air (a cooling gas) to cool the first and second cooling objects. 
         [0041]    As shown in  FIG. 1 , the projector  1  is provided with an exterior housing  2  constituting the exterior of the projector  1 . 
         [0042]    The exterior housing  2  is formed to have a roughly rectangular solid shape having a top surface section  21 , a bottom surface section  22 , a front surface section  23 , a back surface section  24 , and side surface sections  25 ,  26  located on the right and left sides. 
         [0043]    The top surface section  21  is provided with a pair of grips  211  used when the user grips the projector  1 , or when fixing the projector  1  to the equipment installed on the ceiling or the like. The top surface section  21  is provided with opening sections (not shown) for housing light source devices  31 A,  31 B described later inside the exterior housing  2  in an exchangeable manner, and the opening sections are covered with a cover member  212 . 
         [0044]    Although not shown in the drawings, the bottom surface section  22  is provided with a leg section having contact with an installation surface of an installation stand or the like when the projector  1  is installed on the installation surface. 
         [0045]    The front surface section  23  is provided with an opening section  231  from which a part of a projection optical device  35  constituting an image forming device  3  described later is exposed. 
         [0046]    Although not shown in the drawings, besides the above, the side surface section  26  located on the right side is provided with an inlet for introducing an air located in the outside of the exterior housing  2  to the inside, and the side surface section  25  located on the left side is provided with an outlet for discharging the air located in the inside of the exterior housing  2  to the outside. 
         [0047]    It should be noted that in the following drawings and description, the Z direction represents the proceeding direction (the projection direction) of the light projected from the projection optical device  35 , and the X direction and the Y direction represent directions perpendicular to the Z direction, and perpendicular to each other. Among these directions, the Y direction represents an upward direction (i.e., a direction from the bottom surface section  22  of the exterior housing  2  toward the top surface section  21 ) opposite to the vertically downward direction in the case in which the projector  1  is disposed so that the Z direction is parallel to the horizontal direction in a planar view, and the X direction represents a direction from the left side toward the right side viewed from the Z-direction side (the light proceeding-direction side). 
       Internal Configuration of Projector 
       [0048]      FIG. 2  is a schematic diagram showing an internal configuration of the projector  1 . 
         [0049]    As shown in  FIG. 2 , the projector  1  is provided with the image forming device  3  and a cooling device  4  disposed inside the exterior housing  2  besides the exterior housing  2  described above. Besides the above, although not shown in the drawings, the projector  1  is provided with a control device for controlling the projector  1 , and a power supply device for supplying electronic components constituting the projector  1  with electrical power. 
       Configuration of Image Forming Device 
       [0050]    The image forming device  3  forms and then projects the image corresponding to the image information input from the control device described above. The image forming device  3  is provided with an illumination device  31 , a homogenization device  32 , a color separation device  33 , an electro-optic device  34 , a projection optical device  35 , and an optical component housing  36 . 
         [0051]    Among these constituents, the optical component housing  36  is a box-like housing having the illumination optical axis Ax set inside, and the illumination device  31 , the homogenization device  32 , and the color separation device  33  are disposed at respective positions on the illumination optical axis Ax in the inside of the optical component housing  36 . Further, the electro-optic device  34  and the projection optical device  35  are located outside the optical component housing  36 , but are disposed in accordance with the illumination optical axis Ax. It should be noted that the detailed configuration of the optical component housing  36  will be described later. 
         [0052]    The illumination device  31  is provided with a pair of light source devices  31 A,  31 B disposed so as to be opposed to each other, and a reflecting mirror  31 C disposed between the pair of light source devices  31 A,  31 B. 
         [0053]    The pair of light source devices  31 A,  31 B are each provided with a light source lamp  311 , a reflector  312 , and a housing body  313  for housing the light source lamp  311  and the reflector  312  inside the housing body  313 . Further, these light source devices  31 A,  31 B emit light toward the reflecting mirror  31 C. 
         [0054]    The reflecting mirror  31 C reflects the light beams input from the respective light source devices  31 A,  31 B toward the same direction, and thus, makes the light beams enter the homogenization device  32 . 
         [0055]    The homogenization device  32  homogenizes the illuminance in a plane perpendicular to the central axis of the light beam emitted from the illumination device  31 . The homogenization device  32  has a cinema filter  321 , a first lens array  322 , a UV filter  323 , a second lens array  324 , a polarization conversion element  325 , and an overlapping lens  326 . 
         [0056]    Among these constituents, the polarization conversion element  325  is for uniforming the polarization direction of the light having entered the polarization conversion element  325  into one type, and corresponds to a polarization conversion section according to the invention. 
         [0057]    The color separation device  33  separates the light beam input from the homogenization device  32  into three colored light beams of red (R), green (G), and blue (B). The color separation device  33  has dichroic mirrors  331 ,  332 , reflecting mirrors  333  through  336 , and relay lenses  337  through  339 . 
         [0058]    The electro-optic device  34  modulates each of the colored light beams, which have been separated into, in accordance with the image information, and then combines the colored light beams, which have been modulated, with each other. The electro-optic device  34  has field lenses  340 , liquid crystal panels  341  (the liquid crystal panels for red, green, and blue are denoted by  341 R,  341 G, and  341 B, respectively) as light modulation devices, entrance side polarization plates  342 , and exit side polarization plates  343  disposed for the respective colored light beams, and one color combining device  344 . Among these constituents, as the color combining device  344 , there can be adopted a dichroic prism. It should be noted that the electro-optic device  34  corresponds to an image forming section according to the invention. 
         [0059]    The projection optical device  35  is a projection lens for projecting the light beam (the light beam for forming an image) combined by the color combining device  344  on the projection target surface in an enlarged manner. As such a projection optical device  35 , there can be adopted a combination lens having a plurality of lenses arranged in a lens tube. 
       Configuration of Cooling Device 
       [0060]    The projector  1  is provided with the cooling device disposed inside the exterior housing  2  besides the constituents described above. As shown in  FIG. 2 , the cooling device  4  is provided with a first circulatory cooling device  5  having the first cooling object (e.g., the electro-optic device  34 ) disposed inside a closed housing and for circulating the cooling air to the first cooling object to thereby cool the first cooling object, and a second circulatory cooling device  6  having the second cooling object (e.g., the polarization conversion element  325 ) disposed inside a closed housing and for circulating the cooling air to the second cooling object to thereby cool the second cooling object. Therefore, the first cooling object and the second cooling object are individually cooled by the circulatory cooling devices  5 ,  6 , respectively. 
       Configuration of First Circulatory Cooling Device 
       [0061]      FIG. 3  is a block diagram showing a schematic configuration of the first circulatory cooling device  5 . 
         [0062]    The first circulatory cooling device  5  is for circulating the cooling air located inside the closed space S 1  formed by a first closed housing  511  to distribute the cooling air to thereby cool the first cooling object disposed inside the closed space S 1 , then conducting the heat of the first cooling air having been used for cooling the first cooling object to a first liquid circulating through a circulation flow path to release the heat to the outside of the first closed housing  511 , and then conducting the heat from the first liquid to a second liquid circulating through another circulation flow path to thereby release the heat. It should be noted that the first liquid and the second liquid are designations representing the fact that the liquids circulate in the different circulation flow paths, and can be liquids the same in component as each other. As such liquids, there can be cited water and an antifreeze solution such as propylene glycol. 
         [0063]    As shown in  FIG. 3 , the first circulatory cooling device  5  is provided with a cooling device  51 , a heat absorbing device  52 , a heat radiation device  53 , and a cooling fan  54 . 
       Configuration of Cooling Device 
       [0064]    The cooling device  51  is a circulatory cooling device for circulating the first cooling air located inside the first closed housing  511  to cool the first cooling object described above disposed inside the first closed housing  511 . The cooling device  51  is provided with circulation fans  512  and cooling fans  513  besides the first closed housing  511 . 
         [0065]    The first closed housing  511  is a housing in which the electro-optic device  34  as the cooling object, the circulation fans  512 , the cooling fans  513 , and a heat absorber  521  constituting the heat absorbing device  52  described later are housed, and forms the closed space S 1  in which these constituents are disposed. The first closed housing  511  is configured as a closed structure difficult for the air located outside the first closed housing  511  to flow into the inside of the closed housing  511 . 
         [0066]    The first closed housing  511  has an outer wall section  511 A constituting an outer edge of the first closed housing  511 , and an inner wall section  511 B constituting an inner surface, and a part of the outer wall section  511 A and the inner wall section  511 B is formed of an outer surface section  367  (see  FIG. 7 ) as a part of the optical component housing  36 . By the outer wall section  511 A and the inner wall section  511 B combined with each other, a circulation flow path having an annular shape is formed inside the first closed housing  511 . On the circulation flow path, there is disposed the first cooling object (the electro-optic device  34 ). 
         [0067]    The circulation fans  512  each correspond to a first circulation fan according to the invention, and suction and then eject the cooling air located inside the first closed housing  511  to thereby circulate the cooling air inside the first closed housing  511 . The circulation fans  512  are each formed of an axial fan in the present embodiment, and there are disposed two circulation fans in the vicinity of the heat absorber  521  described later. However, besides this configuration, it is possible for the circulation fan  512  to be formed of a sirocco fan, and the number of the circulation fans  512  can arbitrarily be changed, and further, the circulation fans  512  can be arranged in a dispersed manner. 
         [0068]    The cooling fans  513  each suction the cooling air located inside the first closed housing  511 , and then feed the cooling air to the first cooling object via ducts (not shown). The cooling fans  513  include cooling fans  513 R,  513 G, and  513 B disposed so as to correspond to the respective liquid crystal panels  341  of the electro-optic device  34  described above to feed the cooling air to the respective liquid crystal panels  341 . Such cooling fans  513  are each formed of a sirocco fan in the present embodiment, but can also be formed of an axial fan, and the number of the cooling fans  513  can arbitrarily be changed. 
       Configuration of Heat Absorbing Device 
       [0069]    The heat absorbing device  52  is for absorbing the heat from the cooling air located inside the first closed housing  511  described above, and circulating the first liquid, to which the heat has been conducted, to the heat radiation device  53  located outside the first closed housing  511 . The heat absorbing device  52  has a heat absorber  521 , a tank  522 , a pump  523 , and a plurality of circulation pipes  524 . It should be noted that the heat absorber  521  corresponds to a first cooler according to the invention. 
         [0070]    Among these constituents, the circulation pipes  524  ( 5241  through  5244 ) connect the heat absorber  521 , the tank  522 , and the pump  523 , to the heat radiation device  53  described later so that the first liquid can circulate the inside. 
         [0071]    The heat absorber  521  corresponds to the first cooler according to the invention, and is disposed in the first closed housing  511  described above, and the tank  522  and the pump  523  are disposed outside the first closed housing  511 . 
         [0072]    Among these constituents, the heat absorber  521  is connected to the tank  522  via the circulation pipe  5241 , and is also connected to the heat radiation device  53  via the circulation pipe  5244 . The heat absorber  521  absorbs the heat from the cooling air circulating inside the first closed housing  511  to cool the cooling air, and then conducts the heat thus absorbed to the first liquid circulating inside the heat absorber  521 . The first liquid having been heated by the heat absorber  521  circulates toward the tank  522  via the circulation pipe  5241 . 
         [0073]    The tank  522  is connected to the pump  523  via the circulation pipe  5242 . The tank  522  temporarily stores the first liquid circulating via the circulation pipes  5241  through  5244 . Thus, the first liquid mixed with air or an impurity is inhibited from flowing into the pump  523 . 
         [0074]    The pump  523  pressure-feeds the first liquid having flowed through the circulation pipe  5242  to the heat radiation device  53  via the circulation pipe  5243 . 
       Configuration of Heat Radiation Device and Cooling Fan 
       [0075]    Further, the first liquid having circulated to the heat radiation device  53  is cooled by the cooling air circulated to the heat radiation device  53  from the cooling fan  54 , and then circulates again to the heat absorber  521  via the circulation pipe  5244 . Thus, the first liquid low in temperature circulates through the heat absorber  521 , and the first liquid provided with the heat, which has been absorbed from the cooling air inside the first closed housing  511  by the heat absorber  521 , flows from the heat absorber  521  into the tank  522  via the circulation pipe  5241 . In such a manner, in the heat absorbing device  52 , the first liquid is circulated by driving the pump  523 . 
         [0076]    In such a manner, in the first circulatory cooling device  5 , the electro-optic device  34  as the first cooling object described above is cooled in the circulation flow path while the cooling air is cooled by the heat absorber  521 . 
       Configuration of Second Circulatory Cooling Device 
       [0077]      FIG. 4  is a cross-sectional view showing the second circulatory cooling device  6  and a flow path of the cooling air circulating through the second circulatory cooling device  6 . 
         [0078]    The second circulatory cooling device  6  is for circulating the cooling air located inside the closed space S 2  formed by a second closed housing  7  to distribute the cooling air to thereby cool the second cooling object (e.g., the polarization conversion element  325 ) disposed in the closed space S 2 , then conducting the heat of the second cooling air having been used for cooling the second cooling object to a third liquid circulating to a heat pipe  622  (see  FIG. 5 ) to release the heat to the outside of the second closed housing  7 , and then cooling the third liquid located in the heat pipe  622  by the cooling air fed from the cooling fan (not shown) to a heatsink  631  connected to the heat pipe  622 , and thus releasing the heat described above. It should be noted that third liquid can also be a liquid having the same component. As such a liquid, there can be cited water and an antifreeze solution such as propylene glycol. 
         [0079]    As shown in  FIG. 4 , the second circulatory cooling device  6  is provided with a cooling device  61 , a heat absorbing device  62 , a heat radiation device  63 , and a cooling fan (not shown). 
       Configuration of Cooling Device 
       [0080]      FIG. 5  is a perspective view of the optical component housing  36  and the second circulatory cooling device  6  viewed from an opposite-direction side to the Z direction, and  FIG. 6  is a perspective view of the optical component housing  36  and the second circulatory cooling device  6  viewed from an opposite-direction side to the Y direction. 
         [0081]    The cooling device  61  is a circulatory cooling device for circulating the second cooling air located inside the second closed housing  7  to cool the second cooling object described above disposed inside the second closed housing  7 . In  FIGS. 5 and 6 , the cooling device  61  is provided with a circulation fan  612  in addition to a plurality of ducts  71  through  73  constituting the second closed housing  7 . 
         [0082]    The second closed housing  7  is a housing in which the polarization conversion element  325  as the cooling object, the circulation fan  612 , and the heat absorber  621  constituting the heat absorbing device  62  described later are housed, and forms the closed space S 2  in which these constituents are disposed. The second closed housing  7  is configured as a closed structure difficult for the air located outside the second closed housing  7  to flow in the inside of the second closed housing  7 . 
         [0083]    The second closed housing  7  is constituted by the first duct  71 , the second duct  72 , the third duct  73 , and a part of the optical component housing  36 . Although described later in detail, a part of the optical component housing  36  is constituted by outer side surfaces  361 ,  362  of the optical component housing  36 , a dichroic mirror  331 , and the relay lens  337  (see  FIG. 7 ). Using such a configuration, in the second closed housing  7 , there is formed a circulation flow path having an annular shape. Specifically, as shown in  FIG. 4 , the second cooling object (the polarization conversion element  325 ) described above is disposed on the circulation flow path. 
         [0084]    The circulation fan  612  corresponds to a second circulation fan according to the invention, and suctions and then ejects the cooling air located inside the second closed housing  7  to thereby circulate the cooling air inside the second closed housing  7 . The circulation fan  612  is formed of a sirocco fan in the present embodiment, and is disposed in the vicinity of the heat absorber  621  described later. However, besides this configuration, it is possible for the circulation fan  612  to be formed of an axial fan, and the number of the circulation fans  612  can arbitrarily be changed, and further, the circulation fans  612  can be arranged in a dispersed manner. 
       Configuration of Heat Absorbing Device and Heat Radiation Device 
       [0085]    The heat absorbing device  62  is for absorbing the heat from the cooling air located inside the second closed housing  7  described above, and circulating the third liquid, to which the heat has been conducted, to the heat radiation device  63  located outside the second closed housing  7 . The heat absorbing device  62  has the heat absorber  621  and the heat pipe  622 . It should be noted that the heat absorber  621  corresponds to a second cooler according to the invention. 
         [0086]    Among these constituents, the heat pipe  622  is provided with a flow path, through which the third liquid circulates, located inside. To the heat pipe  622 , there is connected the heatsink  631  as the heat radiation device  63 , and by the cooling air supplied to the heatsink  631 , the heat pipe  622  connected to the heatsink  631  is cooled. Thus, the heat having been absorbed by the heat absorber  621  is released from the inside of the second closed housing  7 . 
         [0087]    In such a manner, in the second circulatory cooling device  6 , the polarization conversion element  325  as the second cooling object described above is cooled in the circulation flow path while the cooling air is cooled by the heat absorber  621 . 
       Configuration of Optical Component Housing 
       [0088]      FIG. 7  is a plan view of the optical component housing  36  of the projector  1  viewed from the Y-direction side,  FIG. 8  is a perspective view showing a part of the optical component housing  36  in an enlarged manner. It should be noted that the optical component housing  36  shown in  FIGS. 7 and 8  is in the state in which the top surface section  369  is removed. 
         [0089]    The optical component housing  36  is provided, as shown in  FIGS. 7 and 8 , with a bottom surface section  360 , outer surface sections  361  through  367 , inner surface section  368 , and a top surface section  369  (see  FIG. 5 ). 
         [0090]    The bottom surface section  360  is formed to have a roughly U shape. From each of outer edges located on the outer side of the bottom surface section  360 , there are disposed the outer surface sections  361  through  367  extending toward the Y direction. Further, in a central portion of the bottom surface section  360 , there is disposed the inner surface section  368  having a roughly triangular shape extending toward the Y direction. The bottom surface section  360 , the outer surface sections  361  through  367 , and the inner surface section  368  are formed integrally. However, the invention is not limited to this configuration, but the bottom surface section  360 , the outer surface sections  361  through  367 , and the inner surface section  368  can also be formed as separated members. 
         [0091]    Further, a part of the bottom surface section  360  corresponding to a position where the polarization conversion element  325  is disposed is provided with an opening section H 1 . 
         [0092]    The outer surface section  361  is a side surface section located on the most X-direction side when viewing the optical component housing  36  from the Y-direction side. The end portion on the opposite-direction side to the Z-direction side of the outer surface section  361  is connected to the outer surface section  362 , and the end portion on the Z-direction side is connected to the outer surface section  367 . The outer surface section  361  is provided with groove sections  3611 ,  3612 , and  3613 . Further, at the positions opposed to the groove sections  3611 ,  3612  of the inner surface section  368 , there are formed groove sections  3681 ,  3682 . Further, at the position opposed to the groove section  3613  of the outer surface section  366 , there is formed a groove section  3661 . The dichroic mirror  331  described above is fitted into the groove sections  3611 ,  3681  from the Y-direction side. Further, the overlapping lens  326  is fitted into the groove sections  3612 ,  3682  from the Y-direction side. Further, the dichroic mirror  332  is fitted into the groove sections  3613 ,  3661  from the Y-direction side. Thus, the dichroic mirrors  331 ,  332  and the overlapping lens  326  are firmly fixed to the optical component housing  36 . 
         [0093]    Among these constituents, the dichroic mirror  331  is fixed to the optical component housing  36  to thereby form a division wall according to the invention together with the optical component housing  36 . In other words, the dichroic mirror  331  constitutes a part of the second closed housing  7  of the second circulatory cooling device  6 . It should be noted that the dichroic mirror  331  corresponds to a second optical component and a reflecting member according to the invention. 
         [0094]    The outer surface section  362  is a side surface section located on the most opposite-direction side to the Z-direction side when viewing the optical component housing from the Y-direction side. The end portion on the X-direction side of the outer surface section  362  is connected to the outer surface section  361  as described above, and the end portion on the opposite direction side to the X-direction side is connected to the outer surface section  363 . The outer surface section  362  has a projection section  3620  projecting toward an opposite direction to the Z direction. As shown in  FIGS. 7 and 8 , in the projection section  3620 , there are disposed the cinema filter  321 , the first lens array  322 , the UV filter  323 , the second lens array  324 , and the polarization conversion element  325 . The first lens array  322  corresponds to the second optical component and a lens according to the invention. 
         [0095]    Further, the outer surface section  362  is provided with a groove section  3621 . Further, at the position opposed to the groove section  3621  of the inner surface section  368 , there is formed a groove section  3683 . The relay lens  337  described above is fitted into the groove sections  3621 ,  3683  from the Y-direction side. Thus, the relay lens  337  is fixed to the optical component housing  36  to thereby form the division wall according to the invention together with the optical component housing  36 . In other words, the relay lens  337  constitutes apart of the second closed housing  7  of the second circulatory cooling device  6 . It should be noted that the relay lens  337  corresponds to the second optical component and the lens according to the invention. 
         [0096]    The outer surface section  363  is a side surface section located on the most opposite-direction side to the X-direction side, and on the most opposite-direction side to the Z-direction side when viewing the optical component housing  36  from the Y-direction side. The end portion on the X-direction side of the outer surface section  363  is connected to the outer surface section  362  as described above, and the end portion on the opposite-direction side to the X-direction side is connected to the outer surface section  364 . Both of the end portions of outer surface section  363  are respectively provided with the groove sections  3631 ,  3632 , and the reflecting mirror  333  is fitted into the groove sections  3631 ,  3632  from the Y-direction side. Thus, the reflecting mirror  333  is firmly fixed to the optical component housing  36 . 
         [0097]    The outer surface section  364  is a side surface section located on the most opposite-direction side to the X-direction side, and opposed to the outer surface section  361  when viewing the optical component housing  36  from the Y-direction side. The end portion on the opposite-direction side to the Z-direction side of the outer surface section  364  is connected to the outer surface section  363  as described above, and the end portion on the Z-direction side is connected to the outer surface section  365 . The outer surface section  364  is provided with groove sections  3641 ,  3642 . Further, at the positions opposed to the groove sections  3641 ,  3642  of the inner surface section  368 , there are formed groove sections  3684 ,  3685 . The relay lens  338  is fitted into the groove sections  3641 ,  3684  from the Y-direction side, and the relay lens  339  is fitted into the groove sections  3642 ,  3685  from the Y-direction side. Thus, the relay lenses  338 ,  339  are firmly fixed to the optical component housing  36 . 
         [0098]    The outer surface section  365  is a side surface section located on the opposite-direction side to the X-direction side, and on the most Z-direction side when viewing the optical component housing  36  from the Y-direction side. The end portion on the opposite-direction side to the Z-direction side of the outer surface section  365  is connected to the outer surface section  364  as described above, and the end portion on the Z-direction side is connected to the outer surface section  366 . The reflecting mirror  334  is fixed to the outer surface section  365 . 
         [0099]    The outer surface section  366  is a side surface section having a U shape, and located on the most Z-direction side when viewing the optical component housing  36  from the Y-direction side. The end portion on the opposite-direction side to the X-direction side of the outer surface section  366  is connected to the outer surface section  365  as described above, and the end portion on the X-direction side is connected to the outer surface section  367 . The reflecting mirror  334  is fixed to the outer surface section  365 . 
         [0100]    Further, the outer surface section  366  is provided with pairs of groove sections  3661 ,  3662 , and  3663 , and the field lenses  340  are fitted into the pairs of groove sections  3661 ,  3662 , and  3663  from the Y-direction side to be fixed to the pairs of groove sections  3661 ,  3662 , and  3663 , respectively. 
         [0101]    The outer surface section  367  is a side surface section located on the most X-Z-direction side when viewing the optical component housing  36  from the Y-direction side, and is disposed at a position opposed to the outer surface side  363  described above. The end portion on the opposite-direction side to the Z-direction side of the outer surface section  367  is connected to the outer surface section  361  as described above, and the end portion on the Z-direction side is connected to the outer surface section  366 . The reflecting mirror  336  is fixed to the outer surface section  367 . 
         [0102]    Further, to the surface on the X-Z-direction side of the inner surface section  368 , there is fixed the reflecting mirror  335 . 
       Enclosed Space in Optical Component Housing 
       [0103]    As described above, the bottom surface section  360  is provided with the opening section H 1 , and the dichroic mirror  331  and relay lens  337  are fixed to the optical component housing  36  so as to surround the opening section H 1 . Thus, the second cooling air having circulated from the opening section H 1  circulates in a space surrounded by the projection section  3620 , the first lens array  322 , and the dichroic mirror  331  and the relay lens  337  in the optical component housing  36 , namely in the closed space S 2 . 
         [0104]    It should be noted that the top surface section  369  is provided with an opening section H 2  (see  FIG. 9 ) disposed on the Y-direction side of the polarization conversion element  325 . Further, the opening sections H 1 , H 2  are formed to have roughly the same shapes as each other. 
       Circulation Flow Path of Cooling Device 
       [0105]      FIG. 9  is a cross-sectional perspective view of the second circulatory cooling device  6  viewed from the opposite side to the light emission direction, and  FIG. 10  is a cross-sectional perspective view of the second circulatory cooling device  6  viewed from a different angle from that in  FIG. 9 . 
         [0106]    As shown in  FIGS. 9 and 10 , the second closed housing  7  of the cooling device  61  is provided with a first duct  71 , a second duct  72 , and a third duct  73 . One of the end portions of the first duct  71  is connected to the opening section H 1  of the bottom surface section  360 . Further, the other of the end portions of the first duct  71  is connected to the circulation fan  612 . 
         [0107]    One of the end portions of the second duct  72  is connected to a suction port of the circulation fan  612 . Further, the other of the end portions of the second duct  72  is connected to an end portion of the third duct  73 . As described above, the heat absorber  621  is disposed in the second duct  72 , and the second cooling air circulating through the second duct  72  is cooled by the heat absorber  621 . 
         [0108]    One of the end portions of the third duct  73  is connected to the second duct  72 , and the other of the end portions is connected to the opening section H 2  provided to the top surface section  369 . Further, as described above, the dichroic mirror  331  and the relay lens  337  disposed in the optical component housing  36  constitute a part of the second closed housing  7 . 
         [0109]    According to such a configuration, the ducts  71  through  73 , the first lens array  322 , the dichroic mirror  331 , the relay lens  337 , and the optical component housing  36  form the closed space S 2 . Further, due to the drive of the circulation fan  612 , the second cooling air circulates in the closed space S 2  as shown in  FIG. 4 . Therefore, the polarization conversion element  325  as the second cooling object is cooled. 
         [0110]    The projector  1  according to the present embodiment described hereinabove exerts the following advantages. 
         [0111]    Since the electro-optic device  34  as the first cooling object and the polarization conversion element  325  as the second cooling object are respectively cooled by the first circulatory cooling device  5  and the second circulatory cooling device  6  separated from each other, it is possible to appropriately cool each of the first cooling object and the second cooling object, and control the first cooling object and the second cooling object at an appropriate temperature. 
         [0112]    Here, in the case in which the first cooling object and the second cooling object are respectively disposed at positions distant from each other, if the first and second cooling objects are cooled with a single circulatory cooling device, the circulatory cooling device grows in size. In contrast, according to the present embodiment, the first circulatory cooling device  5  and the second circulatory cooling device  6  can be downsized compared to the case of cooling the first cooling object (the electro-optic device  34 ) and the second cooling object (the polarization conversion element  325 ) with the single circulatory cooling device. Further, by separately disposing the first circulatory cooling device  5  and the second circulatory cooling device  6 , the freedom of arrangement of the first circulatory cooling device  5  and the second circulatory cooling device  6  in the projector can be enhanced. Therefore, the projector  1  can be downsized. 
         [0113]    Since the polarization conversion element  325  can individually be cooled by the second circulatory cooling device  6 , the temperature of each of the electro-optic device  34  and the polarization conversion element  325  can more appropriately be managed. 
         [0114]    Since the division walls constituting the second closed housing  7  are constituted by the optical component housing  36 , the dichroic mirror  331 , and the relay lens  337 , the number of parts can be reduced, and at the same time, downsizing can be achieved compared to the case of constituting the second closed housing  7  only by other parts. Further, since the first closed housing  511  and the second closed housing  7  are separated from each other by the optical component housing  36 , the dichroic mirror  331 , and the relay lens  337 , the electro-optic device  34  and the polarization conversion element  325  can surely be cooled, and can be controlled at an appropriate temperature. 
         [0115]    Since the dichroic mirror  331  constitutes a part of the division wall (the second closed housing  7 ), the second closed housing  7  can surely be constituted by the dichroic mirror  331 . 
         [0116]    Further, since the relay lens  337  constitutes a part of the division wall (the second closed housing  7 ), the first closed housing  511  and the second closed housing  7  can surely be constituted by the relay lens  337 . 
         [0117]    The first cooling air and the second cooling air circulating in the first closed housing  511  and the second closed housing  7  can be cooled by the heat absorber  521  and the heat absorber  621 , respectively. Therefore, the electro-optic device  34  and the polarization conversion element  325  can surely be cooled by the first cooling air and the second cooling air, respectively. 
       Second Embodiment 
       [0118]    Then, a second embodiment of the invention will be described. 
         [0119]    A projector according to the present embodiment is provided with substantially the same configuration as that of the projector  1  described above, but is different in the cooling object to be cooled by the cooling device  61  of the second circulatory cooling device  6 . Specifically, the present embodiment is different from the first embodiment described above in the point that a phosphor wheel is adopted as the second cooling object instead of the polarization conversion element  325 . It should be noted that in the description below, a part which is the same or substantially the same as the part having already been described is denoted by the same reference symbol, and the description thereof will be omitted. 
         [0120]      FIG. 11  is a schematic diagram showing the circulation flow path and the cooling object of the second cooling air in the cooling device  61  according to the present embodiment. 
         [0121]    The cooling device  61  constituting the second circulatory cooling device  6 A according to the present embodiment circulates the second cooling air in the second closed housing  7  to thereby cool the phosphor wheel  8 . Therefore, in the present embodiment, a solid-state laser source (not shown) is used as the light source instead of the light source device  31 A and the light source device  31 B. 
         [0122]    The phosphor wheel  8  is provided with a substrate  81 , a wavelength conversion layer  82 , and an electric motor  83 . The substrate  81  is formed to have a disk-like shape viewed from the Z-direction side, and is constituted by a member having a light transmissive property. Further, on the surface on the Z-direction side of the substrate  81  having the disk-like shape, there is formed the wavelength conversion layer  82  having a doughnut shape. The wavelength conversion layer  82  has a function of being excited by the excitation light having entered the wavelength conversion layer, and emitting fluorescent light (yellow light) converted from the excitation light. In other words, the wavelength conversion layer  82  includes phosphor excited by the excitation light described above. 
         [0123]    Further, to a roughly central part of the substrate  81 , there is connected the electric motor  83 , and it is arranged that the substrate  81  rotates by the drive of the electric motor  83 . 
         [0124]    In the cooling device  61  of the second circulatory cooling device  6 A, when the circulation fan  612  is driven, the second cooling air circulates in the second closed housing  7  as shown in  FIG. 11 . Further, since the second cooling air circulates through the substrate  81  rotating due to the drive of the electric motor  83  toward the Y direction, the phosphor wheel  8  can efficiently be cooled. 
         [0125]    According to the projector related to the present embodiment described hereinabove, the following advantages are exerted in addition to the advantages of the projector  1  according to the first embodiment. 
         [0126]    The phosphor wheel  8  (the wavelength conversion layer  82 ) can individually be cooled by the second circulatory cooling device  6 . Thus, the temperature of each of the electro-optic device  34  and the phosphor wheel  8  can be controlled at more appropriate temperature. 
       Modifications of Embodiments 
       [0127]    The invention is not limited to each of the embodiments described above, but includes modifications, improvements, and so on in the range where the advantages of the invention can be achieved. 
         [0128]    In each of the embodiments described above, it is assumed that the polarization conversion element  325  and the phosphor wheel  8  are cooled by the second circulatory cooling device  6 . However, the invention is not limited to this configuration. For example, it is also possible to assume that the first lens array  322  or the second lens array  324  is cooled as the cooling object. In other words, the second cooling object to be cooled by the second circulatory cooling device  6  can be any optical component as long as the second cooling object is an optical component. 
         [0129]    In each of the embodiments described above, it is assumed that the first cooling air and the second cooling air are circulated for cooling the first cooling object and the second cooling object, respectively. However, the invention is not limited to this configuration. It is also possible to cool each of the cooling objects by circulating a gas other than air. 
         [0130]    In each of the embodiments described above, it is assumed that the first closed housing  511  is separated by the outer surface section  367  of the optical component housing  36 , and the second closed housing  7  is separated by the optical component housing  36 , the dichroic mirror  331 , and the relay lens  337 . However, the invention is not limited to this configuration. It is not required for a part of the first closed housing  511  and a part of the second closed housing  7  to be constituted by the optical component housing  36 , or by the optical component housing  36 , the dichroic mirror  331 , and the relay lens  337 . For example, it is not required for the second closed housing  7  to be provided with the relay lens  337 . In this case, the relay lens  338  functions as the division wall described above. 
         [0131]    In each of the embodiments described above, it is assumed that the cooling device  51  of the first circulatory cooling device  5  is provided with the heat absorber  521 , and the cooling device  61  of the second circulatory cooling device  6  is provided with the heat absorber  621 . However, the invention is not limited to this configuration. For example, it is not required to provide the heat absorbers  521 ,  621 . In this case, it is also possible to, for example, separately provide a cooling section for cooling each of the first closed housing  511  and the second closed housing  7 . 
         [0132]    In the second embodiment described above, it is assumed that the substrate  81  of the phosphor wheel  8  rotates due to the drive by the electric motor  83 . However, the invention is not limited to this configuration. It is also possible to arrange that, for example, a fin or the like, with which the second cooling air circulating in the second closed housing  7  described above collides, is disposed on a surface on the opposite-direction side to the Z-direction side of the substrate  81 . According to this configuration, since the substrate  81  described above is rotated by the second cooling air described above, it is possible to cool the phosphor wheel  8  without providing the electric motor  83 . 
         [0133]    In each of the embodiments described above, it is assumed that the transmissive liquid crystal panels  341  ( 341 R,  341 G, and  341 B) are used as the light modulation device. However, the invention is not limited to this configuration. It is also possible to use, for example, reflective liquid crystal panels instead of the transmissive liquid crystal panels  341  ( 341 R,  341 G, and  341 B). In this case, it is also possible to perform color separation and color composition using the color combining device  344  without providing the color separation device  33 . 
         [0134]    In each of the embodiments described above, it is assumed that the projector  1  is equipped with the three liquid crystal panels  341  ( 341 R,  341 G, and  341 B), but the invention is not limited to this configuration. Specifically, the invention can also be applied to a projector using two or less liquid crystal panels, or four or more liquid crystal panels. 
         [0135]    Further, it is also possible to use a digital micromirror device or the like instead of the liquid crystal panels. 
         [0136]    In the first embodiment described above, it is assumed that the projector  1  is provided with the pair of light source devices  31 A,  31 B. However, the invention is not limited to this configuration. For example, the number of the light source devices can be one, or four. 
         [0137]    In each of the embodiments described above, the image forming device  3  is configured to have a roughly U shape, but the invention is not limited to this configuration. For example, it is also possible to adopt an image forming device configured to have a roughly L shape. 
       CROSS REFERENCE TO RELATED APPLICATIONS 
       [0138]    This application claims priority to Japanese Patent Application No. 2015-079016 filed on Apr. 8, 2015, the entire contents of which are incorporated by reference herein.