Abstract:
A cooling module for use with a DMD module of a projection apparatus is provided. The cooling module comprises a heat conduction device, at least one heat pipe, and at least one fin. Heat accumulating on the DMD module can be released from the heat conduction device to the fins through the heat pipe. Meanwhile, the fins partially overlap along the direction of the light coming from the light source. Thus, the fins can also prevent the unused light in the casing of the projection apparatus from leakage.

Description:
[0001]    This application claims priority to Taiwan Patent Application No. 095130631 filed on Aug. 21, 2006, 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 relates to a cooling module. In particular, the invention relates to a cooling module for use with a DLP projector. 
         [0005]    2. Descriptions of the Related Art 
         [0006]    Many consumers have chosen to use projectors as their display equipments in offices, homes, and conference rooms. There are two types of conventional projectors: liquid crystal display (LCD) projectors or digital light processing (DLP) projectors. Because DLP projectors apply digital projecting and displaying technologies, they are extremely welcome in the display market. 
         [0007]    DLP projectors employ DMD (digital micromirror device) modules as their core technology. The DMD module is composed of a micro mirrors array, fabricated by semiconductor manufacturing processes. Each mirror is a display pixel. When light is projected onto the DMD module from a light source, the micro mirrors of the DMD immediately reflect the light towards the projection lens for image formations according to its image signals. 
         [0008]    However, light possesses energy itself When light hits the DMD module, heat is subsequently generated. Effective cooling for the DMD module quickly turns into an important issue. Conventionally, heat conduction pad, which also work with fans for cooling, have been attached to the DMD modules. A well known DLP projector  10  is shown in  FIG. 1 . The light that is generated from a light source  11  is partially projected onto a DMD module  15  and through an optical engine  13  for image formations. In general, the DMD module  15  is adjacently in contact with the heat conduction pad  16  to prevent heat accumulation thereon. At least one fan  12  is disposed inside the DLP projector  10  for generating cooling airflows. These cooling airflows can be utilized to cool the pad  16  on the DMD module  15  or even other components in the system as well. 
         [0009]    Because the watts and efficiency of the light source  11  have progressively increased in response to the increased use of high-lumen projectors, energy (e.g. light and heat) accumulated on the DMD module  15  has also increased. The use of a larger pad or having greater airflows does not sufficiently cool the DMD module  15 . The size of the pad  16  and the rotational speed of the fan  12  have to be controlled according to the size of the product and the noise level. Consequently, it has been increasingly difficult to cool the DMD module  15 . Overheats may shorten the DMD module  15  life or even terminate the operation of the projection apparatus early. 
         [0010]    Besides, venting apertures  191  are usually disposed on the housing  19  to promote cooling airflows for the DLP projector  10 . These venting apertures  191  provide a channel between the interior of the system and the surroundings for heat exchange. With respect to this kind of heat generating system, venting apertures  191  are essential in design. However, due to the light source  11  with high luminance in the projector, partial light which is generated from the light source  11  and is not guided into the optical engine for the DMD module  15  may leak out from the housing  19  and through the venting apertures  191 . As a result, this light not only causes discomfort in the user&#39;s eye, but also causes light pollution in the projection environment, affecting the projection performance. Moreover, the high temperature may damage the housing  19  and increase the risk of injury to users. Conventionally, a light shelter  17  is usually disposed adjacent to the venting apertures  191  to prevent light from leakage or the user from directly seeing through the light source  11  from the exterior of the system. To block these light leakages, the light shelter  17  disposed on the venting apertures  191  raises airflow resistance instead, which does not benefit for cooling the interior of the DLP projector  10 . Furthermore, the increase in airflow resistance may also raise system noises. 
         [0011]    Given the above, a novel cooling module that can shield light for use in a projection apparatus is needed in this field. 
       SUMMARY OF THE INVENTION 
       [0012]    The primary objective of this invention is to provide a cooling module for use with a projection apparatus. A heat pipe and a fin are included to release accumulated heat on the DMD module. Thus, the cooling efficiency of the DMD module is subsequently increased, extending its lifetime thereof. 
         [0013]    Another objective of this invention is to provide a cooling module for use with a projection apparatus. The fins can provide rapid heat dissipation and also shelter the scattered light from the light source by partially overlapping along the direction of the light source. 
         [0014]    To achieve the abovementioned objectives, the present invention discloses a cooling module for use with a projection apparatus which includes a DMD module. The cooling module comprises a heat conduction device in contact with the DMD module, at least one heat pipe, and at least one fin. The heat pipe has a first portion and a second portion which connects to the first portion in heat conduction. The heat pipe connects to the heat conduction device at the first portion thereof, while the fin connects with the second portion of the heat pipe. Thereby, heat generated from the DMD module for processing light can be outwardly removed from the heat conduction device through the heat pipe and the fin. Furthermore, fins can partially and mutually overlap to provide a light sheltering capability. 
         [0015]    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 
         [0016]      FIG. 1  is a schematic view illustrating the interior of a conventional DLP projector; 
           [0017]      FIG. 2  is a schematic view illustrating the interior of the projection apparatus of the present invention; 
           [0018]      FIG. 3  is a schematic view illustrating the cooling module of the present invention; 
           [0019]      FIGS. 4A to 4C  are schematic views illustrating the embodiments of the heat conduction device of the present invention; 
           [0020]      FIG. 5  is a schematic view illustrating another preferred embodiment of the projection apparatus of the present invention; 
           [0021]      FIG. 6  is a schematic view illustrating a preferred embodiment of the heat conduction device as shown in  FIG. 5 ; 
           [0022]      FIG. 7  is a schematic view illustrating another preferred embodiment of the heat conduction device as shown in FIG  5 ; 
           [0023]      FIG. 8  is a schematic view illustrating still another preferred embodiment of the heat conduction device as shown in  FIG. 5 ; 
           [0024]      FIG. 9  is a schematic view illustrating yet another preferred embodiment of the heat conduction device as shown in  FIG. 5 ; 
           [0025]      FIG. 10  is a schematic view illustrating still another preferred embodiment of the projection apparatus of the present invention; and 
           [0026]      FIG. 11  is a schematic plan view illustrating fins connecting with two heat pipes. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0027]      FIG. 2  shows the first embodiment of a projection apparatus  20  of the present invention. In general, the projection apparatus  20  comprises a light source  21 , an optical engine  23 , a DMD module  25 , and a cooling module  30 . The projection apparatus  20  can further comprise other essential components for projection, for example, a print circuit board  26  which is not described herein. In addition, fans  22 ,  24  are appropriately disposed in this embodiment to form cooling airflows in the projection apparatus  20 . The aforementioned components are all disposed within a housing  29  and integrated to perform a projection function. 
         [0028]    The DMD module  25  further comprises a DMD chip  251 , which is utilized to process light provided from the light source  21  with the inputted image signals. Thus, the DMD chip  251  is one of the principal heat generating portions in the DMD module  25 . The cooling module  30  of the present invention is utilized to cool the DMD module  25  and specifically cool the DMD chip  251  of the DMD module  25 . 
         [0029]      FIG. 3  is a schematic view illustrating the cooling module  30 . The cooling module  30  generally consists of a heat conduction device  31 , at least one heat pipe  33 , and at least one fin  35 . In this embodiment, one heat pipe  33  and a plurality of fins  35  are illustrated. The heat pipe  33  has a first portion  331  and a second portion  333  in which the first portion  331  connects to the heat conduction device  31  and the second portion  333  connects through the plurality of fins  35 . Because the first portion  331  and the second portion  333  are in heat conduction, heat generated from the DMD module  25  for processing light can be outwardly removed from the heat conduction device  31  through the heat pipe  33  and the fins  35 . In this case, the heat conduction device  31  is in contact with the DMD module  25 ; more specifically, in contact with the DMD chip  251 . In actuality, the heat pipe  33  can be integrally formed with the heat conduction device  31 , or alternatively, the heat pipe  33  can be welded or adhered to the heat conduction device  31  during the manufacturing process. 
         [0030]    A cross-sectional view of the heat conduction device  31  is shown in  FIG. 4A  as another embodiment. The heat conduction device  31  includes a contact portion  311  which has a first surface  311   a  and a second surface  311   b  opposite to the first surface  311   a.  In application, the first surface  311   a  can be adjacently in contact with the DMD chip  251  while the first portion  331  of the heat pipe  33  can connect to the second surface  311   b.  Preferably, the heat conduction device  31  further comprises a heat conduction base  313  adjacent to the second surface  311   b  of the contact portion  311 . As compared with the contact portion  311 , the heat conduction base  313  possesses a greater area for enhancing heat dissipating efficiency. More specifically, the first portion  331  of the heat pipe  33  is completely embedded in the heat conduction base  313  and in contact with the second surface  311   b  of the contact portion  311 . More preferably, at least one base fin  313   a  (or any other simple heat conduction device) is formed on the outer surface of the heat conduction base  313  which is opposite to the contact portion  311 . Increasing the base fin  313   a  will increase the heat exchange area and thus promote the cooling efficiency. 
         [0031]      FIG. 4B  and  FIG. 4C  show other embodiments of the heat conduction device  31 . Unlike the aforementioned embodiment, the first portion  331  of the heat pipe  33  is attached onto the outer surface of the heat conduction base  313  and is opposite to the contact portion  311  as shown in  FIG. 4B . In  FIG. 4C , the first portion  331  of the heat pipe  33  is partially embedded in the heat conduction base  313  from the outer surface thereof. 
         [0032]    It is noted that the heat conduction base  313  and the base fin  313   a  illustrated in  FIGS. 4A ,  4 B, and  4 C are only utilized to enhance the cooling efficiency, not as essential elements in the embodiments. 
         [0033]    With reference to  FIG. 2 , the cooling module  30  of the present invention further comprises a fan  22  disposed adjacent to the fins  35 . The fan  22  is suitable for generating a cooling airflow  221  which assists in outwardly dissipating hot air through the fins. Therefore, an airflow field can be generated from the cooling airflow  221  flowing in the projection apparatus  20 . This airflow field can also cool other components. Preferably, the location of the fan  22  should be adjustable and thus guides the cooling airflow  221  substantially towards the interior of the projection apparatus  20  or more preferably, towards the light source  21 . Generally, because the light source  21  is the main heat generating portion in the projection apparatus  20 , the cooling airflow  221  directed at the light source  21  will help cool the light source  21 . 
         [0034]    Furthermore, a plurality of venting apertures  291  can be disposed on the housing  29  of the projection apparatus  20  to facilitate the formation of the airflow field. These venting apertures  291  can also coincide with other fans  24  to facilitate cooling other components in the projection apparatus  20 . For example, in  FIG. 2 , the fans  24  are disposed opposite to the plurality of venting apertures  291  to draw airflows. This process can fully and efficiently contribute to the interior airflow field. Certainly, the positions of the fans  24  are not limited. The fans can be alternatively disposed on the same side of the venting apertures  291  or other substitute locations. 
         [0035]    In the ideal situation, light generated by the light source  21  should be guided into the optical engine  23  for projection. Nevertheless, scattering light is inevitable. For simplicity, light generated from the light source  21  will be differentiated into a first part and a second part herein (not shown in the figures). The first part of the light is guided into the optical engine for projection, while the second part of the light, which is not usable, scatters outward from the optical engine. Heat accumulated on the DMD module  25  results from the first part of the light generated by the light source  21 , while the second part of the light may scatter outward from the housing  29 , causing imperfections in the use and quality of the performance. 
         [0036]    The second embodiment of the present invention provides an arrangement for dealing with the scattered second part of the light. As shown in  FIG. 5 , the cooling module  30  of the present embodiment works with fans  24  to generate airflow for cooling the fins  35  and also to shelter the second part of light from the light source  21 . 
         [0037]      FIG. 6  illustrates a schematic view of the cooling module  30  of the present embodiment. The plurality of fins  35  is disposed substantially along a lengthwise direction of the second portion  333  of the heat pipe  33 , and successively parallel to one another. Consequently, a plurality of parallel spaces is formed for venting airflows and dissipating hot air. For simplicity, each of the fins  35  can be defined as having a first edge  351  and a second edge  353 . The first edge  351  is opposite to the second edge  353  in view of the second portion  333  of the heat pipe  33 . Each of the first edges  351  partially overlaps with the second edge  353  of the adjacent fin thereof along the illuminating direction S (as shown in  FIG. 6  with broken lines) which is construed by the second part of light generated by the light source  21 . In this embodiment, each of the fins  35  forms a substantially non-orthogonal angle with the second portion  333  of the heat pipe  33  and then forms overlaps for light sheltering. Alternatively, if each of the fins  35  forms an orthogonal angle with the second portion  333  of the heat pipe  33 , the fins  35  do not provide light sheltering. 
         [0038]    Another embodiment of the plurality of fins  35  is shown in  FIG. 7 . Each of the fins  35  has a fin body portion  350  and a bending portion  352  which connects with the fin body portion  350 . The first edge  351  is formed on the fin body portion  350  while the second edge  353  is formed on the bending portion  352 . Specifically, the fin body portion  350  forms a substantially orthogonal angle with the second portion  333  of the heat pipe  33 , while the bending portion  352  forms a substantially non-orthogonal angle with the second portion  333  of the heat pipe  33 . The fins  35  have a plurality of bending portions  352  to increase the overlapping. Thus, the bending portion  352  and the fin body portion  350  at least partially overlap along the direction S of the second part of the light, generated by the light source  21 , for shelter. 
         [0039]    Another preferred embodiment is shown in  FIG. 8 . The bending portions  352  are respectively formed on the first edge  351  and the second edge  353  of the fins  35 . More preferably, these two groups of bending portions  352  are disposed opposite each other. This can facilitate overlap formations along the direction S of the second part of the light. 
         [0040]      FIG. 9  shows still another preferred embodiment of the present invention. In this embodiment, the fin body portion  350  has a cambered shape. Thus, a deviation is formed from the center to the first edge  351  and the second edge  353  of each fin  35 . Overlaps for light sheltering can still be formed along the direction S of the second part of the light. 
         [0041]    The cooling module  30  of the present invention is not limited to be formed with a single heat pipe. As shown in  FIG. 10 , the second portion  333  of the heat pipe  33  has two sections that form an included angle therewith, and the fins  35  disposed on the heat pipe  33  are distributed on the two sections. Even though the plurality of heat pipes are not illustrated in the figures, either the first portion or the second portion of the heat pipe  33  is expected to be disposed with the fins  35  in plurality. Aforementioned embodiments can help cool the DMD module  25 . For example, when the fins  35  of the present invention collaborate with the plurality of heat pipes  33 , the fin body portion  350  has two holes which connect with two heat pipes  33  therethrough as shown in  FIG. 11 . To achieve the predetermined cooling efficiency, the way that the holes are to be designed depends on how many that the heat pipes  33  are given. 
         [0042]    According to the aforementioned disclosures, the cooling module  30  of the present invention uses the heat pipe  33  and the fins  35  to enhance the cooling efficiency of the DMD module  25 . The fins  35  can not only provide rapid cooling but also shelter light due to the overlaps between the fins  35 . The conventionally disposed light shelter plate would be economized. This design thus benefits the DLP apparatus that contributes a narrow interior and an effective airflow field. 
         [0043]    In addition, the fans  24  and the venting apertures  291  can be disposed on opposite sides, same sides or any other positions in the projection apparatus  20 . Furthermore, the fans  24  can either draw or blow airflows. All of these can be adapted in the embodiments as shown in  FIG. 5  and FIG  10 . 
         [0044]    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.