Abstract:
An air-cooling apparatus which cools an imaging unit with a plurality of LCD panels and a polarizer assembly includes a cooling fan, and a cooling duct which directs air expelled from the cooling fan onto the plurality of LCD panels and the polarizer assembly, and the cooling duct includes a plurality of channels corresponding to the plurality of LCD panels, and at least two channels from among the plurality of channels are bent in a vertical direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from Korean Patent Application No. 10-2010-0041961, filed in the Korean Intellectual Property Office on May 4, 2010, the disclosure of which is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Aspects of the exemplary embodiments relate to an air-cooling apparatus which cools an imaging unit having a plurality of liquid crystal display (LCD) panels and a display apparatus having the same. 
         [0004]    2. Description of the Related Art 
         [0005]    An imaging unit which is used for a beam projector or a projection television forms a color image using an LCD panel with one or three LCD panels (red, green, and blue), and the LCD panels project an image on a projection screen along with the light projected from a light source. 
         [0006]    Generally, a high-luminance light source consumes more electric power than a low-luminance light source and could cause thermal damage to the LCD panel when light is penetrated or concentrated on the LCD panel. If thermal damage occurs on the LCD panel and a polarizer which is formed on the front portion of the LCD panel, image quality and contrast deteriorate due to color change. 
         [0007]    Therefore, a display apparatus which forms a screen by gathering light has a channel for airflow to cool the LCD panel of an optical module and the polarizer. 
         [0008]    If there is only one LCD panel, an air-cooling channel may be formed without any problem. However, if there are multiple LCD panels and polarizers for red, green and blue colors respectively, a cooling fan should be installed for each LCD panel and polarizer or more than two cooling fans should be installed to form an airflow channel. If a plurality of cooling fans are used, set volume as well as noise may increase. Alternatively, if a duct is used to form an airflow channel instead of a cooling fan, the length of the airflow channel is extended, decreasing cooling capability. 
       SUMMARY OF THE INVENTION 
       [0009]    Exemplary embodiments relate to an air-cooling apparatus of which structure is improved to reduce the number of parts, cut manufacturing cost, and make the set smaller and quieter, and a display apparatus having the same. 
         [0010]    According to an aspect of an exemplary embodiment, there is provided an air-cooling apparatus which cools an imaging unit with a plurality of LCD panels and a polarizer assembly, the air-cooling apparatus including a cooling fan which expels air and a cooling duct which directs air expelled from the cooling fan onto the plurality of LCD panels and the polarizer assembly, and the cooling duct includes a plurality of channels corresponding to the plurality of LCD panels, and at least two channels from among the plurality of channels are bent vertically. 
         [0011]    The plurality of LCD panels may include red, green, and blue LCD panels and the polarizer assembly may include red, green, and blue LCD polarizers, and the cooling duct may include a first channel which blows air onto the red LCD panel and a red polarizer, a second channel which blows air onto the green LCD panel and a green polarizer, and a third channel which blows air onto the blue LCD panel and a blue polarizer. 
         [0012]    The first and the second channels may be branched horizontally relative to one another, and the second and the third channels may be branched vertically relative to one another. 
         [0013]    The first channel may be narrower than the second channel, and the second and the third channels may be have a same width. 
         [0014]    The first channel may include a first air flow direction changing member, a second channel may include a second air flow direction changing member, and the third channel may include a third air flow direction changing member, wherein the first, second, and third air flow direction changing members refract air flow from a horizontal direction to a vertical direction perpendicular to the horizontal direction, and the first and the third air flow direction changing members may be installed higher in the vertical direction than the second air flow direction changing member. 
         [0015]    The discharge nozzle may include a plurality of first discharge nozzles which respectively cool the red, green, and blue LCD panels and a plurality of second discharge nozzles which respectively cool the red, green, and blue polarizers, and the second discharge nozzles may be disposed inside the first discharge nozzles. 
         [0016]    The first and second discharge nozzles may have a same height. 
         [0017]    According to an aspect of another exemplary embodiment, there is provided a display apparatus including a lighting system a projection system, and an imaging unit, and an air-cooling apparatus which cools the imaging unit by air. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The above and/or other aspects will be more apparent by describing certain exemplary embodiments with reference to the accompanying drawings, in which: 
           [0019]      FIG. 1  is an explosive perspective view illustrating an air-cooling apparatus according to an exemplary embodiment; 
           [0020]      FIG. 2  is a perspective view illustrating a second housing in  FIG. 1 ; 
           [0021]      FIG. 3  is a bottom view of a first housing in  FIG. 1 ; 
           [0022]      FIG. 4  is an assembly perspective view illustrating an air-cooling apparatus according to an exemplary embodiment; 
           [0023]      FIG. 5  is a bottom perspective view of  FIG. 4 ; 
           [0024]      FIG. 6  is a view illustrating a flow of cooling-air in a red LCD panel; and 
           [0025]      FIG. 7  is a view illustrating a flow of cooling-air in a green LCD panel. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Certain exemplary embodiments are described in greater detail below with reference to the accompanying drawings. 
         [0027]    In the following description, like drawing reference numerals are used for the like elements, even in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of exemplary embodiments. However, exemplary embodiments can be practiced without those specifically defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the application with unnecessary detail. 
         [0028]    As illustrated in  FIG. 1 , an air-cooling apparatus  100 , according to an exemplary embodiment, includes a first housing  200 , a cooling duct  300 , a second housing  400 , and a cooling fan  500 . 
         [0029]    An imaging unit comprising red, green, and blue LCD panels  110 ,  120 ,  130 , red, green, and blue polarizers  111 ,  121 ,  131  which are installed on the red, green, and blue LCD panels  110 ,  120 ,  130  respectively, and a prism  140  which distributes light received from an illuminating system (not shown) to the LCD panels  110 ,  120 ,  130  is installed on the upper portion of the first housing  200 . 
         [0030]    The second housing  400  is installed on the lower portion of the first housing  200 , and the cooling duct  300  is formed by combination of the first housing  200  and the second housing  400 . The cooling fan  500  is coupled to the cooling duct  300  and draws in surrounding air and expels the drawn-in air to the outside, and may be for example a centrifugal fan. 
         [0031]    The cooling duct  300  is formed by combination of the first housing  200  and the second housing  400 , and includes a first to a third channels  310 ,  320 ,  330  (as shown in  FIG. 3 ) including a duct entrance  301 , an air flow direction changing member  302 , and a discharge nozzle  303 . 
         [0032]    The first channel  310  blows air into the red LCD panel  110  and the red polarizer  111 , the second channel  320  blows air into the green LCD panel  120  and the green polarizer  121 , and the third channel  330  blows air into the blue LCD panel  130  and the blue polarizer  131 . 
         [0033]    In this case, the second channel  320  may be branched from the first channel  310  in a horizontal direction and extended for a predetermined distance, and then may be bent at 85 to 95 degrees in an “L” shape with respect to the first channel, forming a bending unit, which includes a convex surface. The third channel  330  may be branched from the second channel  320  in a vertical direction and extended for a predetermined distance, and may be bent at degrees in an “L” shape with respect to the second channel, forming a bending unit, which includes a convex surface. As illustrated in  FIG. 3 , the width W 1  of the first channel  310  may be narrower than the width W 2  of the second channel  320 , and the second channel  320  and the third channel  330  have similar width. 
         [0034]    The duct entrance  301  is formed on the first housing  200 , and one end of the duct entrance  301  is coupled and sealed to the cooling fan  500 . The width W of the duct entrance  301  is formed to correspond to the width of the exit  510  of the cooling fan  500 . The branching plate  305  is formed in the adjacent duct entrance  301  to be branched in a horizontal direction with respect to the first channel  310  and the second channel  320 . The end of the branching plate  305  is designed to be sharp so as to facilitate the branching of the cooling-air which is drawn in from the cooling fan  500 . 
         [0035]    The air flow direction changing member  302  is formed on a bottom of the second housing  400  and refracts the direction of air flowing out of the cooling fan  500 . The air flow direction changing member  302  may be formed separately, or may be formed integrally with the second housing  400  when the second housing  400  is injection-molded. As illustrated in  FIG. 2 , the air flow direction changing member  302  includes the first to the third air flow direction changing members  321 ,  322 ,  323  which have a round shape and formed on the first to the third channels  310 ,  320 ,  330  respectively. As illustrated in  FIG. 2  and  FIG. 6 , the first to the third air flow direction changing members  321 ,  322 ,  323  refracts a direction from which air has flown in from the cooling fan  500  in a horizontal direction as marked with arrow A into a vertical direction as marked with arrow B. 
         [0036]    As illustrated in  FIG. 2 , the second air flow direction changing member  322  may be disposed higher than the first and the third changing members  321 ,  323  by being installed on an upper portion of a support rib  332   a  having a predetermined height h. 
         [0037]    The discharge nozzle  303  is formed to spray the air drawn in from the cooling fan  500  in the upward direction from below the plurality of LCD panels  110 ,  120 ,  130  and the polarizers  111 ,  121 ,  131 . The discharge nozzle  303  includes first discharge nozzles  331   a ,  332   a ,  333   a  which cool the LCD panels  110 ,  120 ,  130  and second discharge nozzles  331   b ,  332   b ,  333   b  which cool polarizers  111 ,  121 ,  131 . The second discharge nozzles  331   b ,  332   b ,  333   b  may be disposed inside the first discharge nozzles  331   a ,  332   a ,  333   a , i.e., closer to one another than the first discharge nozzles. 
         [0038]    Hereinafter, the operation of an air-cooling apparatus, according to an exemplary embodiment, will be explained with reference to relevant drawings. As illustrated in  FIG. 5 , the present air-cooling apparatus guides air flowing from the cooling fan  500  into the red LCD panel  110  and the red polarizer  111 , the green LCD panel  120  and the green polarizer  121 , and the blue LCD panel  130  and the blue polarizer  131  through the first to the third channels  310 ,  320 ,  330 . 
         [0039]    The air drawn into the duct entrance  310  is divided into the first and the second channels  310 ,  320  by the branching plate  305 . In this case, the width of the first channel  310  may be narrower than the width of the second channel  320 . That is because the red LCD panel  110  produces relatively small amount of heat, and thus it can be cooled off with relatively small amount of cooling air, while the green LCD panel  120  and the blue LCD panel  130  require more cooling air to be cooled off. 
         [0040]    As illustrated in  FIG. 6 , the direction of the air drawn into the first channel  310 , marked with arrow A, is changed by the first air flow direction changing member  321  into a vertical direction, and thus the air moves in the upward direction, marked with arrow B, from below the red LCD panel  110 . In this case, the location and shape of the first air flow direction changing member  321  may be adjusted so that air may pass through the center of the red LCD panel  110 . For instance, the round angle of the first air flow direction changing member  321  may be adjusted, or the location of the first air flow direction changing member  321  may be moved so that the central axis of cooling air may pass through the center (CL) of the red LCD panel  120 . 
         [0041]    The air drawn into the second channel  320  may flow through the center (CL) of the green LCD panel  120 . Since the second air flow direction changing member  322  installed on the second channel  320  is formed on the upper portion of the support rib  332   a  having a predetermined height h, the second air flow direction changing member  322  is disposed relatively higher than the first and the third air flow direction changing members  321 ,  323  which are installed on the first and the third channels  310 ,  330 . Accordingly, the air passing through the second channel  320  is branched into an upper portion and a lower portion with respect to the second air flow direction changing member  322 , and a relatively large amount of air is emitted along the convex surface of the second air flow direction changing member  322  towards the green LCD panel  120  (see the direction marked with arrow C,  FIG. 7 ), and the remaining air moves towards the third channel  330  (see the direction marked with arrow D,  FIG. 7 ). Since the green LCD panel  120  among the red, green, blue LCD panels  110 ,  120 ,  130 , receives most heat, and therefore requires a large amount of air to cool off the panel, a relative large amount cooling air is provided to the green LCD panel  120 . The second and the third channels  320 ,  330  are branched into upper and lower portions and the same width is maintained so that the second channel  320  has the same width as the third channel  330 . Therefore, speed loss of the air flowing through the channel may be minimized. 
         [0042]    The direction of the cooling air drawn into the third channel  330  is changed by the third air flow direction changing member  323  which is disposed having the same height as the first air flow direction changing member  321  installed in the first channel  310 . Although not illustrated, the direction of air is changed into a vertical upward direction similar to the first and the second air flow direction changing members  321 ,  322  so that air flows upwards from below the blue LCD panel  130  as in the red and green LCD panels  110 ,  120 . The location of the third air flow direction changing member  323  may be adjusted so that the center of the cooling air may pass through the center of the blue LCD panel  130 . 
         [0043]    According to an exemplary embodiment, the first to the third channels  310  to  330  may be formed stereoscopically, and thus the three LCD panels  110  to  130  and polarizers  111 ,  121 ,  131  may be fully cooled off by a single cooling fan  500 . Particularly, since the second channel  320  and the third channel  330  are branched into upper and lower portions and therefore the width of the cooling duct  300  can be maintained constantly, cooling performance may be enhanced by minimizing speed loss of the cooling air flowing through the cooling duct  300 . 
         [0044]    According to an exemplary embodiment, three LCD panels and three polarizers may be cooled by a single cooling fan, and thus it is possible to reduce the number of parts, cut manufacturing cost, and make the set smaller and quieter. 
         [0045]    Although a few exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these exemplary embodiments without departing from the principles and spirit of the inventive concept, the scope of which is defined in the claims and their equivalents.