Abstract:
The outdoor display apparatus has a display unit, a blowing unit which generates air along the display unit, and a channel part which emits the air passed the display unit, wherein the channel part is extended to the lower part of the displaying unit from its side part, and at least a portion of the channel part is laid underground.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on Japanese Patent Application No. 2011-018492 filed on Jan. 31, 2011, the contents of which are hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a display apparatus, specifically relates to an outdoor display apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    In recent years, large-sized display apparatuses called “digital signage” which are deployed outdoors, and display information such as advertising information are emerging. 
         [0006]    When these apparatuses are installed outdoors, liquid crystal panel may not operate properly due to heat caused by sunlight. Thus, it is necessary to employ a structure for cooling the panel. 
         [0007]    One idea is to employ a fan for generating an air flow and thereby cooling the liquid crystal panel. 
         [0008]    Further, the inventors of the present application has focused an attention to the fact that while the thermal conductivity of air is about 0.026 [W/m.K], the thermal conductivity of the ground is as large as 0.62. By notifying this characteristic, the inventors have invented a display apparatus which can further improve the cooling capability. 
       SUMMARY OF THE INVENTION 
       [0009]    The display apparatus of the present invention comprises a display unit, a blowing unit which generates air along the display unit, and a channel part which emits the air passed the display unit, wherein the channel part is extended to the lower part of the displaying unit from its side part, and at least a portion of the channel part is laid underground. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a front perspective view of the display apparatus  1 . 
           [0011]      FIG. 2  is a sectional view of the apparatus  1 , showing its cooling structure from the above. 
           [0012]      FIG. 3  is a sectional view of the apparatus  1 , showing its cooling structure from the front side. 
           [0013]      FIG. 4  is a sectional view of the apparatus  1 , showing its cooling structure from the left side. 
           [0014]      FIG. 5  is a sectional view of the display apparatus  100 , showing its cooling structure from the front side. 
           [0015]      FIG. 6  is a sectional view of the display apparatus  100 , showing its cooling structure from the left side. 
           [0016]      FIG. 7  is a sectional view of the display apparatus  200 , showing its cooling structure from the left side. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    The embodiments of the present invention are described below. 
       First Embodiment 
       [0018]      FIG. 1  is a front perspective view of the display apparatus  1  regarding to the first embodiment of the present invention. As shown in the figure, in the apparatus  1 , a display unit  4  formed by a liquid crystal panel is accommodated in a casing consisted by a front cabinet  2  and a back cabinet  3 . On the right side (when viewed from the front side) of the cabinet, an intake duct  11  is attached, and on the left side of the cabinet, an exhaust duct  12  is attached. 
         [0019]      FIG. 2  is a sectional view describing a cooling structure of the apparatus  1 , when viewed from its upper side.  FIG. 3  is another sectional view describing the cooling structure, when viewed from its front side. 
         [0020]    Inside the cabinet, the display unit  4  comprising a display panel  44  and a backlight  45  is formed. In the backside of the unit  4 , a power supply part  60   a  for supplying a power supply to the unit  4 , and a control circuit  60   b  for controlling an operation of the unit  4  are arranged. 
         [0021]    In the front side of the display panel  44 , a transparent front glass  13  for protecting the display panel  44  is arranged. In the front side of this glass  13 , a transparent sheet-like touch panel  46  is arranged. This touch panel  46  is detects the variation of an electric capacity caused by an approach of people&#39;s finger. 
         [0022]    The image displayed on the display panel  44  is viewable through the front glass  13  and the touch panel  46 . 
         [0023]    Between the front side of the display panel  44  and the front glass  13 , a space  10  for passing air is provided. On the right side of the space  10 , an inlet  14  is provided, and on the left side of the space  10 , an outlet  15  is provided. On the right side of the inlet  14 , an air intake duct  11  is provided and on the left side of the outlet  15 , an air exhaust duct  12  is provided. Further, an air intake fan  49   a  is arranged in the inlet  14 , and air exhaust fan  49   b  is arranged in the outlet  15 . 
         [0024]    Referring to  FIG. 3 , inlets  14 , the outlets  15 , intake fans  49   a,  and exhaust fans  49   b  are formed in three places such that they align in the up-and-down direction. Namely, the inlets consists of inlet  14   a,    14   b,  and  14   c,  the outlets consists of outlet  15   a,    15   b,  and  15   c,  the fans  49   a  consists of fan  49   a   1 ,  49   a   2 , and  49   a   3 , and the fans  49   b  consists of fan  49   b   1 ,  49   b   2 , and  49   b   3 . Further, in each of the inlets  14  or outlets  15 , a filter for preventing rain or dust from going inside the display apparatus  1  may be arranged. The cooling fans  49  consist of the fans  49   a  and the fans  49   b.    
         [0025]    By rotating the cooling fans  49 , the airflow  80  from the inlet  14  to the outlet  15  is generated as shown by arrows in  FIG. 2  or  3 . Thereby, an airflow  80  between the inlet  14  and outlet  15  is generated inside the space  10  (i.e. the space between the display panel  44  and the front glass  13 ). By this airflow  80 , the liquid crystal panel  44  is cooled. 
         [0026]    Referring to  FIG. 3 , the intake duct  11  has a structure such that it covers three inlets  14  from their outer sides. Similarly, the exhaust duct  12  has a structure such that it covers three outlets  15  from their outer sides. 
         [0027]    The lower part of the ducts  11  and  12  are laid underground (see  FIG. 4  also). The ducts  11  and  12  communicate each other underground via communicating duct  13 . Thereby, the heat generated from the liquid crystal panel  44  is led underground by the exhaust fan  49   b  through exhaust duct  12 . Further, since the exhaust duct  12  and the intake duct  11  are communicated by the duct  13 , the circulation pass of the air is formed. 
         [0028]    Assuming that the temperature of the heat emitted from the liquid crystal panel  44  is 50 degrees Celsius, for example, and the temperature of the ground is 15 degrees Celsius, the air led underground via the exhaust duct  12  should be cooled efficiently. The cooled air reaches the liquid crystal panel  44  again through the intake duct  11 . Thereby, the liquid crystal panel is cooled efficiently. 
       Second Embodiment 
       [0029]      FIGS. 5 and 6  are sectional views of a display apparatus  100  regarding to the second embodiment of the present invention. When display apparatus is installed outdoors, either one of the two sides (i.e. front side or back side) becomes a shaded (or shadowed). Thus, it is preferable to radiate heat generated by the panel  44  to this shaded area. In view of this, in the apparatus  100 , a communicating duct  130  for communicating the duct  11  and  12  is bent backward. In other words, the duct  130  is provided so that it is laid underground of the area shaded by the cabinet of the apparatus  100 . Thereby, it can further achieve an efficient cooling. 
       Third Embodiment 
       [0030]      FIG. 7  is a sectional view of a display apparatus  200  regarding to the third embodiment of the present invention. This is a view seen from its left side. The direction of the sun changes depending on the time in a day. Further, depending on the owner of the apparatus  200 , installation direction of the apparatus may be various. In view of this, in the apparatus  200 , the communicating duct, which communicates the duct  11  and  12 , comprises a first duct  141  and a second duct  142 . In the entrance portion of the ducts  141  and  142 , switches SW 1  and SW 2  are provided respectively. Thereby, the air exhausted from the duct  12  can communicate to the duct  11 , selectively by the duct  141  or  142 . 
         [0031]    For example, as shown in  FIG. 7 , when the sunlight is irradiating from the displaying side of the apparatus  100  and the side opposite from the displaying side is becoming a shaded area, heat can be emitted efficiently if an air passed through the duct  12  is entered to the first duct  141  which is in the shaded side rather than the second duct  142 . Thus, SW 1  is set open while SW 2  is set closed. 
         [0032]    On the other hand, depending on time in a day, the sunlight may irradiate from the opposite side of the displaying side and the displaying side may become shaded. For example, in the morning, the sun may shine from the displaying side, and in the evening the sun may shine from the rear side of the displaying side. In such case, it preferable to set SW 1  closed and SW 2  opened. 
         [0033]    Instead of SW 1  and SW 2 , a moving wall may be employed. When the moving wall moves to one side, air from the duct  12  enters to the first duct  141 . When the moving wall moves to another side, air from the duct  12  enters to the second duct  142 . 
         [0034]    The embodiment of the present invention is described as above. However, the scope of the present invention is not limited to this. It can be modified variously within the scope of the present invention without deviating from the spirit thereof. For example, a liquid crystal display panel is explained as an example of the display unit. However, a plasma panel, organic electroluminescence panel, electronic paper, CRT, or an advertising film may be employed instead. 
         [0035]    Instead of emitting the heat generated by the liquid crystal panel using the duct (i.e. hollow-centered component), in which the air flow inside, the heat may be emitted using a component (i.e. solid-core like component) having a high thermal conductivity, such as metal.