Abstract:
A cooling device and a projection device comprising the same are provided. The projection device comprises a lamp and a cooling device. The lamp has a first side and a second side opposite the first side, and one of the two sides is the upper side of the lamp. The cooling device comprises a first blower and a second blower. The first blower is adapted to generate a first airflow towards the first side, while the second blower is adapted to generate a second airflow towards the second side.

Description:
[0001]    This application claims priority to Taiwan Patent Application No. 099144353 filed on Dec. 17, 2010, the disclosures of which are incorporated herein by reference in their entirety. 
       CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention provides a cooling device for a projection device, and more particularly, to a cooling device that can generate and guide airflow of various intensities to cool the lamps. 
         [0005]    2. Descriptions of the Related Art 
         [0006]    Power levels have increased to accommodate the increased improvement of projector luminance. As a result, lamps may generate intensive heat during operation, which produce hot gasses that are concentrated in the upper area of the lamps. To solve the problem of overheating, a cooling device is usually disposed inside the projector to cool the lamp to reduce the damage to the internal parts caused by excessively high temperatures. 
         [0007]    As shown in  FIG. 1A , the cooling device  2  of a projector  1  of the prior art comprises a blower  20  in combination with an airflow guiding plate  21  and is adapted to generate an airflow  201 , an airflow  202  and an airflow  203  towards the front end  11 , lamp wick  12  and back end  13  of the lamp  10  respectively. With further reference to  FIG. 1B , when the projector  1  is used upright (e.g., on a table), hot gasses inside the lamp  10  are concentrated towards the first sidewall  101  so that the first sidewall  101  of the lamp  10  is at a higher temperature and the second sidewall  102  of the lamp  10  is at a lower temperature. Because the blower  20  is located above the lamp  10 , the airflows  201 ,  202  and  203  generated by the blower  20  can cool the temperature of the first sidewall  101  of the lamp  10  easily. However, although this can make the temperature difference between the first sidewall  101  and the second sidewall  102  of the lamp  10  relatively small, it is still not enough to cool down the temperature of the high-power lamp  10 . Moreover, as shown in  FIG. 1C , when the projector  1  is used upside down (e.g., hung from a ceiling), the hot gasses inside the lamp  10  are concentrated toward the second sidewall  102  so that the second sidewall  102  of the lamp  10  is at a higher temperature and the first sidewall  101  of the lamp  10  is at a lower temperature. Because the blower  20  is located below the lamp  10 , the airflows  201 ,  202  and  203  from the blower  20  are unable to cool the second sidewall  102  of the lamp  10  directly, which results in an increased temperature difference between the first sidewall  101  and the second sidewall  102  of the lamp  10  instead. The undue temperature difference has a serious effect on the service life of the lamp  10 ; furthermore, when a high-power lamp is used, the rotating speed of the blower has to be increased to lower the temperature of the lamp, and this will lead to excessive noise. 
         [0008]    To overcome the shortcomings of using a single blower, the cooling device  2  of another projector  1  of the prior art adopts a dual-blower framework to tackle the problem of high temperatures in the lamp  10 . As shown in  FIG. 2A , the blower  20  is used in combination with the airflow guiding plate  21  and generates the airflow  202  and the airflow  203  towards the lamp wick  12  and the back end  13  of the lamp  10  respectively; and the other blower  22  is used in combination with an airflow guiding plate  23  and generates an airflow  221  towards the front end  11  of the lamp  10 . This framework can desirably lower the temperature of a high-power lamp. With further reference to  FIG. 2B , when the projector  1  is used upside down (e.g., hung from a ceiling), the front end  11  of the lamp  10  can still be desirably cooled by the airflow  221  of the blower  22  without being affected, but the hot gasses inside the lamp  10  are concentrated towards the second sidewall  102  of the lamp  10  so that the second sidewall  102  of the lamp  10  is at a higher temperature and the first sidewall  101  of the lamp  10  is at a lower temperature. In addition, the blower  20  is located below the lamp  10 , so neither the airflow  202  nor the airflow  203  of the blower  20  can cool the second sidewall  102  of the lamp  10  directly. Consequently, the temperature difference between the first sidewall  101  and the second sidewall  102  of the lamp  10  increases and leads to a non-uniform temperature distribution at the filament  12  and the back end  13 , which also has an adverse effect on the service life of the lamp  10 . 
         [0009]    In view of this, an urgent need exists in the art to provide a solution that can not only reduce the temperature of the front end and the wick of a lamp effectively, but also minimize the temperature difference between the upper side and the lower side of the lamp by controlling the intensities of airflow no matter how the projector is used. 
       SUMMARY OF THE INVENTION 
       [0010]    An objective of the present invention is to provide a cooling device for a projection device. The projection device comprises a lamp which has a first side and a second side opposite the first side, and either the first side or the second side of the lamp is located at the upper side of the lamp. The cooling device comprises a first blower and a second blower. The first blower is adapted to generate a first airflow towards the first side of the lamp; and the second blower is adapted to generate a second airflow towards the second side of the lamp. 
         [0011]    Another objective of the present invention is to provide a projection device. The projection device comprises a lamp and a cooling device. The lamp has a first side and a second side opposite the first side, and either the first side or the second side of the lamp is located at the upper side of the lamp. The cooling device comprises a first blower and a second blower. The first blower is adapted to generate a first airflow towards the first side of the lamp; and the second blower is adapted to generate a second airflow towards the second side of the lamp. 
         [0012]    According to the above descriptions, by generating airflows of different intensities towards the upper side and the lower side of a lamp respectively and particularly by enhancing the heat dissipation of the upper side of the lamp, the cooling device of the present invention can minimize the temperature difference between the upper side and the lower side of the lamp when the projection device is disposed in different manners (e.g., disposed on a table upright or hung from a ceiling upside down). In this way, the service life of the lamp is prolonged. 
         [0013]    The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1A  is a schematic side view illustrating a lamp of the prior art projector and a single blower of a cooling device; 
           [0015]      FIG. 1B  is a schematic view of airflows of the single blower when the prior art projector is disposed upright; 
           [0016]      FIG. 1C  is a schematic view of the airflows of the single blower when the prior art projector is disposed upside down; 
           [0017]      FIG. 2A  is a schematic side view of airflows of dual blowers when the prior art projector is disposed upright; 
           [0018]      FIG. 2B  is a schematic side view of the airflows of the dual blowers when the prior art projector is disposed upside down; 
           [0019]      FIG. 3  is a schematic side view of a lamp and a cooling device according to the present invention; 
           [0020]      FIG. 4A  is a schematic view of airflows of the cooling device according to the present invention when a projection device is disposed upright; and 
           [0021]      FIG. 4B  is a schematic view of the airflows of the cooling device according to the present invention when the projection device is disposed upside down. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    In reference to  FIG. 3 , a projection device  5  of the present invention comprises a lamp  4  and a cooling device  3 . The lamp  4  can be divided into a front end  41  and a lamp wick  42 , while the cooling device  3  comprises a first blower  31  and a second blower  32 . The first blower  31  is adapted to generate a first airflow  31   a  towards the first side  31  of the lamp  4 , while the second blower  32  is adapted to generate a second airflow  32   a  towards the second side  32  of the lamp  4 . The lamp  4  further defines the first side  401  and second side  402  opposite the first side  401 , and either the first side  401  or the second side  402  is an upper side  43  of the lamp  4 . Thereby, the first airflow  31   a  generated by the first blower  31  flows towards the direction of the first side  401  of the lamp  4 ; and the second airflow  32   a  generated by the second blower  32  flows towards the direction of the second side  402  of the lamp  4 . 
         [0023]    Moreover, to obtain a desirable cooling effect, airflow guiding pipes are usually installed on the blowers by those of ordinary skill in the art to guide and deflect airflows generated by the blowers to different locations of lamps. In this embodiment, a first airflow guiding pipe  311  is disposed between the first blower  31  and the first side  401  to guide the first airflow  31   a ; and a second airflow guiding pipe  321  is disposed between the second blower  32  and the second side  402  to guide the second airflow  32   a . In addition, the first airflow guiding pipe  311  has two airflow outlets  311   a  and  311   b  which are installed to face the front end  41  and the lamp wick  42  respectively; while the second airflow guiding pipe  321  of the second blower  32  has two airflow outlets  321   a  and  321   b  which are installed to face toward the front end  41  and the lamp wick  42  respectively. 
         [0024]    During the actual operation, the first airflow  31   a  generated by the first blower  31  and the second airflow  32   a  generated by the second blower  32  are simultaneously transmitted to the front end  41  and the wick  42  of the lamp  4  through the two airflow outlets  311   a  and  311   b  of the first airflow guiding pipe  311  and the two airflow outlets  321   a  and  321   b  of the second airflow guiding pipe  321  respectively. In this way, the temperature of the lamp  4  can be cooled uniformly. 
         [0025]    In view of the fact that hot gasses inside the lamp  4  tend to be concentrated towards the upper side  43  of the lamp  4 , the intensities of the different airflows are controlled to obtain a desirable cooling effect at the upper side  43  of the lamp  4 . In this embodiment, in reference to  FIG. 4A  (where the projection device  5  is disposed upright on a table), the first side  401  of the lamp  4  is located at the upper side  43  of the lamp  4 ; and in this case, the first airflow  31   a  generated by the first blower  31  is controlled to be stronger than the second airflow  32   a  generated by the second blower  32 . In contrast, as shown in  FIG. 4B  (where the projection device  5  is hung from a ceiling upside down), the second side  402  of the lamp  4  is located at the upper side  43  of the lamp  4 ; and in this case, the second airflow  32   a  generated by the second blower  32  is controlled to be stronger than the first airflow  31   a  generated by the first blower  31 . Therefore, no matter whether the projection device  5  is disposed upright (e.g., on a table) or upside down (e.g., hung from a ceiling), airflows blown to the upper side of the lamp  4  is always stronger than those blown to the lower side of the lamp  4 . This leads to a small temperature difference between the first side  401  and the second side  402  of the lamp  4 , thus prolonging the service life of the lamp  4  more effectively. 
         [0026]    In this embodiment, the cooling device  3  may further comprise a tilt sensor  34  or an On-Screen Display (OSD) controller  35  (not shown) for determining which of the first side  401  and the second side  402  is located at the upper side  43  of the lamp  4  and operating the first blower  31  and the second blower  32  of the lamp  4  to control the intensities of the first airflow  31   a  generated by first blower  31  and the second airflow  32   a  generated by a second blower  32 . In this way, the orientation in which the projection device  5  is disposed can be determined to strengthen the intensity of the airflows blown to the upper side  43  of the lamp  4 . 
         [0027]    According to the above descriptions, apart from cooling the front end and the lamp wick of the lamp, the cooling device of the present invention can also particularly enhance the heat dissipation effect at the upper side of the lamp by controlling the intensities of the airflows blown toward the upper side depending on the orientation in which the projection device is disposed. In this way, the temperature difference between the upper side and the lower side of the lamp is minimized and, consequently, the service life of the lamp is prolonged. 
         [0028]    The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.