Abstract:
An optical engine is provided, including an imaging module, a driver module and a connecting unit. The imaging module includes an imaging housing with an imaging space and an imaging unit installed in the imaging space. The imaging housing is made of a conductive material. The driver module includes a driver housing with a driver space and a driver circuit board installed in the driver space. The connecting unit includes at least one of the cables is electrically connected to the imaging unit and the driver circuit board and at least a protruding module protruding from the imaging housing (or the driver housing) to contact with the driver housing (or the imaging housing). The cable is installed in the protruding module made of a conductive material.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority of Taiwan Patent Application No. 096140056, filed on Oct. 25, 2007, the entirety of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a projection system, and more particularly, to an optical engine for improving electromagnetic interference for a projection system. 
         [0004]    2. Description of the Related Art 
         [0005]    Common household or commercial projection systems are regulated and inspected for electromagnetic waves. Electromagnetic interference from projection systems affects other electronic devices and even interferes with operations thereof. Thus, electromagnetic interference is prevented by using projection systems passing electromagnetic wave inspections. 
         [0006]    There are many electric components generating electromagnetic waves in a projection system. For an imaging unit generating images, for example an LCos (Liquid Crystal on Silicon) display, a cable transmits high frequency imaging signals from an independent driver module, thus, electromagnetic waves with high frequency are generated along the cable. If electromagnetic waves with high frequency are not decreased, an imaging unit will not pass electromagnetic wave safety inspections. A conventional solution is to cover a copper foil on the cable, and then stick an adhesive tape on the cable to electrically connect the cable to a metal housing. If inspection requirements are still not met, a metal sheet is further provided to cover the cable, thus decreasing leakage by sealing in the electromagnetic waves. However, to improve electromagnetic interference, the above-mentioned solution requires additional materials and increased assembly steps. Thus, increasing costs and time needed for repair and replacement. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    The invention provides an optical engine for improving electromagnetic interference. 
         [0008]    The invention provides an optical engine comprising an imaging module, a driver module and a connecting unit. The imaging module comprises an imaging housing with an imaging space and an imaging unit installed in the imaging space. The imaging housing is made of a conductive material. The driver module comprises a driver housing with a driver space and a driver circuit board installed in the driver space. The connecting unit comprises at least one of the cables is electrically connected to the imaging unit and the driver circuit board and at least a protruding module protruding from the imaging housing (or the driver housing) to contact with the driver housing (or the imaging housing). The cable is installed in the protruding module made of a conductive material. 
         [0009]    The efficacy of the invention is that the imaging house is electrically connected to the driver housing via the protruding module. Thus, the imaging module and the driver module form a close loop and conductive environment. Thus, shielding effect shields electromagnetic waves generated by the cable in the imaging space and the cable in the protruding module. At least one of the cables is electrically connected to the imaging unit and the driver circuit board for improving electromagnetic interference. The optical engine achieves the goal of the invention. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]      FIG. 1  is a schematic view of an embodiment of an optical engine that improves electromagnetic interference according to the invention; 
           [0011]      FIG. 2  is an exploded view of the embodiment in  FIG. 1 ; 
           [0012]      FIG. 3  is a cross-sectional view that shows a connecting unit along hatches III-III; 
           [0013]      FIG. 4  is a schematic view of another embodiment of an optical engine that improves electromagnetic interference according to the invention; and 
           [0014]      FIG. 5  is an exploded view of the embodiment in  FIG. 4 . 
       
    
    
       [0015]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Referring to  FIGS. 1-3 ,  FIGS. 1-3  show an embodiment of an optical engine of the invention for improving electromagnetic interference. The optical engine comprises a light source module  1 , an imaging module  2 , a driver module  3 , a connecting unit  4  and a lens  5 . 
         [0017]    The light source module  1  provides light for the imaging module  2  and the lens  5 . 
         [0018]    The imaging module  2  comprises an imaging housing with an imaging space  211 , and a light management unit  22  and an imaging unit  23  disposed in the imaging space  211 . The imaging housing  211  comprises an imaging cover  212  and an imaging bottom  213  for forming the imaging space  211 . In this embodiment, the light management unit  22  may be an X-cube for splitting or combining various colored lights. The imaging unit  23  comprises three LCoS (Liquid Crystal on Silicon) displays  231  for generating images. 
         [0019]    The driver module  3  near the imaging module  2  comprises a driver housing  31  with a driver space  311  made of a conductive material, and a driver circuit board  32  in the driver space  311  driving the imaging unit  23 . The driver housing  31  comprises a driver cover  312  and a driver bottom  313  for forming the driver space  311 . 
         [0020]    The connecting unit  4  comprises three cables electrically connected to the LCoS displays  231  of the imaging unit  23  and the driver circuit board  32 , respectively, and three protruding modules  42  protruding from the imaging housing  21  and contacting with the driver housing  31 . Each of the protruding modules  42  comprises a first protrusion  421  protruding from the imaging cover  212  and contacting with the driver cover  312 , and a second protrusion  422  protruding from the imaging bottom  213  and contacting with the driver bottom  313 . The first protrusion  421  is separated from and faces to the second protrusion  422 . The first protrusion  421  and the second protrusion  422  are made of a conductive material. Each of the cables  41  are installed between the first protrusion  421  and the second protrusion  422  of the protruding module  42 . In this embodiment, the gaps between the first protrusions  421  and the second protrusions  422  are less than 3 mm. 
         [0021]    One end of the lens  5  is installed in the imaging module  2  and the other end of the lens  5  protrudes out of the imaging module  2  for outputting and projecting images. 
         [0022]    Concerning electromagnetic interference, the following describes how embodiments of the invention improve electromagnetic interference. High frequency imaging signals are transmitted from the driver circuit board  32  to the imaging unit  23  via the cables  41  for imaging, thus, a high electromagnetic wave is generated. However, in the embodiment of the invention, the first protrusions  421  and the second protrusions  422  of the protruding modules  42  are electrically connected to the imaging module  2  and the driver module  3 . That is to say, the first protrusions  421  and the second protrusions  422  work as bridges to join the imaging module  2  and the driver module  3 . The imaging module  2  and the driver module  3  form a close loop and conductive environment. Thus, the cables  41  electrically connected to the imaging unit  23  and the driver circuit board  32  are well shielded, whether disposed in the image module  2  or the driver module  3 , substantially decreasing electromagnetic wave leakage. The purpose of improvement in the leakage of the electromagnetic waves is arrived. 
         [0023]    Note that the first protrusions  421  and the second protrusions  422  may protrude from the image module  2  and contact with the driver module  3 . Or the first protrusions  421  and the second protrusions  422  may protrude from the driver module  3  and contact with the image module  2 . Or the first protrusions  421  and the second protrusions  422  may respectively protrude from different modules. The above-mentioned structures all improve the leakage of the electromagnetic waves. In order to increase the electric conductivity between the first protrusions  421  and driver cover  312  and between the second protrusions  422  and driver bottom  313 , the connecting unit  4  further comprises three first conductive elastic elements  43  respectively connected to the first protrusions  421  and the driver cover  312 , and three second conductive elastic elements  44  respectively connected to the second protrusions  422  and the driver bottom  313 , increasing the connecting efficiency and the electric conductivity between the first protrusions  421 , the second protrusions  422  and the driver module  3 , thus, improving shielding effect. Similarly, in order to increase the electric conductivity between the first protrusions  421  and the cables  41  and between the second protrusions  422  and the cables  41 , the connecting unit  4  further comprises three third conductive elastic elements  45  respectively connected to the first protrusions  421  and the cables  41 , and three fourth conductive elastic elements  44  respectively connected to the second protrusions  422  and the cables  41 , increasing the connecting efficiency and the electric conductivity between the first protrusions  421 , the second protrusions  422  and the cables  41 , thus, also improving shielding effect. 
         [0024]    Referring to  FIGS. 4 and 5 ,  FIGS. 4 and 5  show another embodiment of the optical engine that can improve electromagnetic interference according to the invention. The difference between  FIGS. 4-5  and  FIGS. 1-3  is that the connecting unit  4  in this embodiment only comprises one protruding module  42  and the protruding module  42  comprises a first protrusion  421 ′ and a second protrusion  422 ′. The sizes of the first protrusion  421 ′ and the second protrusion  422 ′ are large enough to cover the three cables  41 . Namely, the first protrusion  421  and the second protrusion  422  in  FIGS. 1-3  are individual. Alternatively, the first protrusion  421 ′ and the second protrusion  422 ′ in  FIGS. 4 and 5  act like a combined first protrusion  421  and the second protrusion  422  to form a unitary and single member. The mold and the assembly process of this embodiment are simplified, thus, decreasing costs. 
         [0025]    In summary, the above-mentioned embodiments of the optical engine of the invention improve electromagnetic interference. Advantages of the embodiments of the optical engine of the invention are as follows: 
         [0026]    First, electromagnetic interference is improved. The image module  2  is electrically connected to the driver module  3  via the first protrusion  421  and the second protrusion  422  for forming a bridge between two modules  2  and  3 , making the image module  2  and the driver module  3  forms a close loop and conductive environment via the first protrusion  421  and the second protrusion  422 . The cables  41  electrically connected to the imaging unit  23  and the driver circuit board  32  are well shielded, substantially decreasing electromagnetic wave leakage, whether disposed in the image module  2 , the driver module  3  or between the first protrusion  421  and the second protrusion  422 . 
         [0027]    Second, repair and replacement is simplified. The optical engine of the invention improving electromagnetic interference does not use a copper foil and an adhesive tape to cover the cables like a conventional projection system, but only uses the first protrusion  421  and the second protrusion  422  to form a close loop and conductive environment. Thus, when repairing, all that is required is to open the covers  212  and  312  for repair. Dismantling a copper foil and an adhesive tape is avoided, thus, simplifying repair and replacement of the optical engine. 
         [0028]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.