Abstract:
A heat dissipation assembly for a projection apparatus is provided. The projection apparatus includes a light source, optical elements and a heat dissipation assembly. The heat dissipation assembly includes a case, a heat dissipation element, a fan and a temperature controlling unit. The optical elements transmit a light beam generated by the light source, and thereby generate heat. The heat dissipation assembly is adapted for heat dissipation correspondingly. In the heat dissipation assembly, the case protects the optical elements from being polluted by the dust during heat dissipation. The temperature controlling unit senses the surrounding temperature to control the fan for cooling the heat dissipation element, and the durability of the optical elements are thereby enhanced.

Description:
[0001]    This application claims the benefit from the priority of Taiwan Patent Application No. 100101370 filed on Jan. 14, 2011, the disclosures of which are incorporated by reference herein 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 relates to a heat dissipation assembly, and in particular, to a heat dissipation assembly for use in a projection apparatus. 
         [0005]    2. Descriptions of the Related Art 
         [0006]    Because consumers have gravitated towards projection apparatuses with higher definition and more vivid colors, projection apparatuses have had to be designed to keep competitive in the market. Correspondingly, demands on the projection luminance of the projection apparatuses have also increased. However, the increase in luminance inevitably leads to a higher operating temperature of optical elements, which transmit light rays in the projection apparatuses. 
         [0007]    More specifically, due to the residual energy remaining in the light transmission process, heat accumulates among the optical elements and leads to a temperature rise in the whole projection apparatus. An excessively high temperature would adversely affect the light transmission and reduce the service life of the optical elements, so a heat dissipation element must be provided for cooling. Accordingly, heat dissipation has become an important problem to be overcome in the development of projection apparatuses. 
         [0008]    A conventional way to dissipate heat is to open a hole on the case of a projection apparatus and to dispose a fan in the hole. Then when the fan operates, an air flow would be driven from outside and flow into the projection apparatus to cool the optical elements in the projection apparatus. However, despite having the optical elements directly exposed to the air outside the apparatus to help in the cooling process, dust from the surroundings may be brought into the inner elements with the airflow. Consequently, the efficiency of the optical elements in transmitting the light rays might be degraded and cause a decrease in the projection luminance. In some circumstances, the optical elements might even be damaged. 
         [0009]    Accordingly, an urgent need exists in the art to provide a heat dissipation assembly that is not susceptible to pollutants in the air and, meanwhile, improve the luminance of the projection apparatus through heat dissipation to provide consumers with better visual experiences and to improve the stability and prolong the service life of the optical elements in the projection apparatus. 
       SUMMARY OF THE INVENTION 
       [0010]    An objective of the present invention is to provide a heat dissipation assembly that can effectively prevent pollutants from the surrounding air from entering the heat dissipation assembly, while also improving the luminance and dissipating heat. 
         [0011]    To achieve the aforesaid objective, the present invention provides a heat dissipation assembly disposed within a projection apparatus. The projection apparatus comprises a light source, a plurality of optical elements and the heat dissipation assembly. The light source is adapted to generate a light beam, the plurality of optical elements are adapted to transmit the light beam, and the heat dissipation assembly is adapted to dissipate heat from the optical elements. 
         [0012]    The heat dissipation assembly comprises a case, a heat dissipation element, a first fan and a temperature controlling unit. The case is adapted to receive at least one of the optical elements of the projection apparatus; the heat dissipation element is disposed on a surface of the case; the first fan is disposed outside the case; and the temperature controlling unit is electrically connected to the first fan and comprises a temperature sensor for sensing the temperature around the temperature sensor. 
         [0013]    When the projection apparatus operates, heat is accumulated among the optical elements due to transmission of the light beam. The heat is transmitted to the heat dissipation element by heat convection or heat transfer, and is then dissipated outwards through the heat dissipation element. Meanwhile, the temperature controlling unit senses a surrounding temperature and controls the fan to develop a cooling air flow according to the control unit to lower the temperature and increase the heat exchange speed between the heat dissipation element and the outside. 
         [0014]    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 
         [0015]      FIG. 1  is a schematic view of a projection apparatus according to a first embodiment of the present invention; 
           [0016]      FIG. 2  is a schematic view of a projection apparatus according to a second embodiment of the present invention; 
           [0017]      FIG. 3  is a schematic view of a projection apparatus according to a third embodiment of the present invention; 
           [0018]      FIG. 4  is a schematic view of a projection apparatus according to a fourth embodiment of the present invention; 
           [0019]      FIG. 5  is a schematic view of a projection apparatus according to a fifth embodiment of the present invention; 
           [0020]      FIG. 6  is a schematic view of a projection apparatus according to a sixth embodiment of the present invention; and 
           [0021]      FIG. 7  is a schematic view of a projection apparatus according to a seventh embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    The present invention provides a heat dissipation assembly and a projection apparatus with the same. In the following descriptions, the present invention will be explained with reference to the embodiments thereof. However, it should be appreciated that the following descriptions of these embodiments are only intended to illustrate but not to limit the present invention. Meanwhile, in the following embodiments and the attached drawings, elements unrelated to the present invention are omitted from depiction; and dimensional relationships among individual elements in the attached drawings are illustrated only for ease of understanding, but not to limit the actual scale. 
         [0023]    The first embodiment of the present invention is a projection apparatus  1 , a schematic view of which is shown in  FIG. 1 . The projection apparatus  1  comprises a housing  11 , a light source  13 , an optical element set  15  and a heat dissipation assembly. The housing  11  is adapted to receive and protect components inside the projection apparatus  1  (i.e., the light source  13  and the optical element set  15  in this embodiment). The light source  13  is adapted to generate a light beam. The optical element set  15  comprises a plurality of optical elements adapted to transmit the light beam and convert the light beam into images for projection outwards. 
         [0024]    As shown in  FIG. 1 , the heat dissipation assembly comprises a case  21 , a heat dissipation element, a first fan  25  and a temperature controlling unit  27 . The case  21  is adapted to sealingly encapsulate the optical element set  15  therein to protect all optical elements of the optical element set  15  from ambient pollution. In this embodiment, the case  21  is preferably formed integrally, and the light source  13  is preferably disposed between the housing  11  and the case  21 . Additionally, in practical application, foam may be disposed at the welding, where the case  21  is closed to improve the sealing capability of the case from dust entry. The heat dissipation element comprises four first cooling fins  23   a  and four second cooling fins  23   b . The first cooling fins  23   a  are disposed on four sides of an outer surface of the case  21  respectively; while the second cooling fins  23   b  are disposed on four sides of an inner surface of the case  21 . The second cooling fins  23   b  are disposed corresponding to the first cooling fins  23   a  respectively. The second cooling fins  23   b  are adapted to transfer heat generated from the optical element set  15  to the first cooling fins  23   a , and thus be dissipated outwards. In this embodiment, the cooling fins  23   a ,  23   b  are formed integrally with the case  21  as shown in  FIG. 1  to make the heat transfer process smoother, although the present invention is not limited thereto. Preferably, the case  21  of the present invention is made of a metal, while the first cooling fins and the second cooling fins are made of aluminum (Al) or copper (Cu). 
         [0025]    The first fan  25  is disposed outside the case  21 , and more specifically, the first fan  25  in this embodiment is disposed at an interior edge of the housing  11 . When the first fan  25  operates, air flow (as shown by the dashed lines with arrows) inside the housing  11  can be effected to enhance the heat dissipation efficiency. The number and locations of the first fans  25  of the present invention are not limited to what is described in this embodiment, but may be modified by those skilled in the art depending on the practical heat dissipation requirements. 
         [0026]    The temperature controlling unit  27  comprises a temperature sensor (not shown) disposed on an inner surface of the case  21  and electrically connected to the first fan  25 . In response to the temperature condition retrieved by the temperature sensor, the temperature controlling unit  27  produces a controlling signal to the first fan  25  to generate an air flow or further adjusts a rotation speed of the first fan  25  to change the velocity of the air flow. A faster air flow could increase the efficiency of the heat dissipating. Through the air flow generated by the first fan  25 , the heat accumulated in the optical element set  15  due to the transmission of the light beam can be dissipated by the heat dissipation element to the outside of the case  21 . 
         [0027]      FIG. 2  illustrates a schematic view of a projection apparatus  2  according to the second embodiment of the present invention. The projection apparatus  2  of this embodiment is similar to the projection apparatus  1  of the first embodiment, and the main difference there between is that the first fan  25  of the heat dissipation assembly of the second embodiment is disposed near the outer surface of the case  21 , so that the heat dissipating efficiency of the wall surfaces and the first cooling fins  23   a  is enhanced. In other embodiments, the manner in which the first fan disposed in the first embodiment and that in the second embodiment may be used in combination by those skilled in the art, i.e., the first fan is provided on the surface of each of the housing  11  and the case  12 , and this can further improve the overall heat dissipation efficiency of the projection apparatus. 
         [0028]    A projection apparatus  3  according to the third embodiment of the present invention is shown in  FIG. 3 . The projection apparatus  3  is also similar to the projection apparatus  1  of the first embodiment, but further comprises a second fan  35 . The second fan  35  is disposed inside the case  21  to uniform the air temperature inside the case  21  more quickly. This helps to decrease the hotspot temperature of the optical elements and enhance the heat dissipation efficiency of the second cooling fins  23   b . Similarly, the number of second fans to be used in other embodiments is not limited, but may be altered depending on the heat dissipation requirements; and furthermore, the first fan(s) and the second fan(s) may also be used in the same projection apparatus simultaneously and the numbers thereof are not limited. 
         [0029]    Preferably, depending on the heat dissipation requirements, the heat dissipation assembly may also comprise a plurality of temperature controlling units; the temperature controlling units may be electrically connected to some or all of the fans. Here, the fans may include the first fan(s)  25  and the second fan(s)  35 . 
         [0030]    A projection apparatus  4  according to the fourth embodiment of the present invention is shown in  FIG. 4 . The projection apparatus  4  of this embodiment is also similar to the projection apparatus  1  of the first embodiment except that the heat dissipation assembly of the fourth embodiment comprises two temperature controlling units  47   a ,  47   b  disposed on the inner surface and the outer surface of the case  21  respectively. Similarly, the temperature controlling units  47   a ,  47   b  are also both electrically connected to the first fan  25  and each comprises a temperature sensor for sensing temperatures inside and outside the case  21  respectively. In response to the temperature, signals are produces from the temperature controlling units  47   a ,  47   b  to the first fan  25  to generate an air flow for cooling purposes. In projection apparatuses of other embodiments, the number of temperature controlling units comprised in the heat dissipation assembly may be altered depending on the heat dissipation requirements; the temperature controlling units may be electrically connected to some or all of the fans. The number and locations of the fans are not limited. 
         [0031]      FIG. 5  illustrates a schematic view of a projection apparatus according to the fifth embodiment of the present invention. In addition to the case  21 , the heat dissipation element, the first fan  25  and the temperature controlling unit  27 , the heat dissipation assembly of this embodiment further comprises a heat pipe  51 , a third cooling fin  53  and a third fan  55 . Furthermore, the heat dissipation element of the heat dissipation assembly comprises three first cooling fins  53   a  and four second cooling fins  53   b.    
         [0032]    The heat pipe  51  has an attachment end  51   a  and a far end  51   b . The attachment end  51   a  is closely attached to the outer surface of the case  21 , while the far end  51   b  is not attached to the case  21  but extends away from the case  21 . The third cooling fin  53  is disposed on the far end  51   b , and a cooling air flow generated by the third fan  55  carries the heat away from the third cooling fin  53 . Thereby, the heat pipe  51  attached to the case  21  can effectively reduce the heat around the case  21  by effectively absorbing the heat from the case  21 . The heat that is carried away from the case  21  could be dissipated by the third cooling fin  53  through the air flow generated by the third fan  55 . 
         [0033]    In reference to  FIGS. 6 and 7 , the heat dissipation assembly of the present invention may also be designed particularly for at least one optical element of the optical element set. A projection apparatus  6  according to the sixth embodiment of the present invention is shown in  FIG. 6 . The projection apparatus  6  of this embodiment comprises a housing  11 , a light source  13 , an optical element set  65  and a heat dissipation assembly. The heat dissipation assembly comprises a case  21 , a heat dissipation element, a first fan  25  and a temperature controlling unit  27 . 
         [0034]    The optical element set  65  of this embodiment comprises an optical element  651 , which abuts the inner surface of the case  21  and cooperates with the case  21  to substantially define an enclosed space. The heat dissipation element comprises four first cooling fins  63   a  and three second cooling fins  63   b . One of the first cooling fins  63   a  is disposed corresponding to the optical element  651  to cool down the optical element  651 . In this embodiment, the optical element  651  may be a mirror or a lens, although it is not merely limited thereto. 
         [0035]      FIG. 7  illustrates a schematic view of a projection apparatus  7  according to the seventh embodiment of the present invention. Similar to the sixth embodiment, the heat dissipation assembly of the projection apparatus  7  comprises a case  21 , a heat dissipation element, a first fan  25 , two temperature controlling units  77   a ,  77   b  and a driving element  79 . The case  21  comprises an periphery edge (not shown) that defines a through hole  210 , while the heat dissipation element comprises four first cooling fins  73   a  and three second cooling fins  73   b.    
         [0036]    In this embodiment, the optical element of the projection apparatus  7  is a color wheel  71  comprising an index board. The color wheel  71  is disposed corresponding to the through hole  210  and abuts on the inner surface of the case  21 . The driving element  79  connects to a sensing board  711  through the through hole  210 . A temperature controlling element  77   a  is also disposed on the inner surface of the case  21  and a temperature controlling element  77   b  is disposed on an inactive surface of the sensing board  711  to sense both the temperature inside the case  21  and the temperature around the sensing board  711  and to generate control signals correspondingly. The control signals are adapted to adjust the rotational speed or turn-on/off of the first fan  25  to improve the heat dissipation efficiency and reduce the energy loss. Preferably, a sealing component (e.g., a foam) is interposed between the driving element  79  and the periphery edge of the through hole  210  to enhance the sealing performance of the case  21 . 
         [0037]    According to the above descriptions, as compared to the heat dissipation design adopted in conventional projection apparatuses, the heat dissipation assembly of the present invention provides a solution that can effectively dissipate heat in an enclosed space, improve the luminance of the projection apparatus, and can protect the internal optical elements against dust and pollutants from outside the case, thus prolonging the service life and enhance the performance of the projection apparatus. 
         [0038]    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.