Abstract:
A high resolution projection system has a light source for generating and emitting light and a plurality of digital micromirror device imagers configured to receive and reflect the light.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a digital micromirror device (DMD) projection system. In particular, the invention relates to a high resolution DMD projection system. 
       BACKGROUND OF THE INVENTION 
       [0002]    With the advent of digital micromirror devices (DMD devices) such as digital light processors (DLPs) there has been a desire to integrate the digital projection technology into cinematic theatres for viewing by the public at large. However, as of yet, DMDs (and DLPs in particular) have not yet progressed in native resolution capability so as to allow an acceptable image for large venues which complies with industry standards for display quality. Particularly, the Society of Motion Picture and Television Engineers (SMPTE) promulgates such standards which are well respected by the various members of the motion picture industry. One such standard applies to the display of a all of a Digital Cinema Distribution Masters (DCDMs) (digital packages which contains all of the sound, picture, and data elements needed for a show) in review rooms and theatres. A requirement of the SMPTE standard is that the pixel count of the projected image must be at least 2048×1080 (2K×1K). The standard further requires that the mesh of pixels (the device structure) must be invisible/imperceptible when viewed from a reference viewing distance. While many DMD/DLP projectors meet the minimum requirement regarding resolution, those same projectors cannot meet the second requirement of the standard since the proper reference viewing distance is small enough to cause visibility of the mesh of pixels. Therefore, current DMD/DLP projectors having 2K×1K resolution are not suitable for most commercial theatres where the viewing distance is small and where to prevent the appearance of the pixel mesh from an appropriate viewing distance, a DMD/DLP projector must have a resolution of about 4K×2K (which is not currently commercially available). 
         [0003]    It is therefore desirable to develop an improved DMD/DLP projection system. 
       SUMMARY OF THE INVENTION 
       [0004]    A high resolution projection system has a light source for generating and emitting light and a plurality of digital micromirror device imagers configured to receive and reflect the light. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a schematic illustration of a high resolution digital micromirror device projection system according to an embodiment of the present invention; and 
           [0006]      FIG. 2  is a schematic illustration of a high resolution digital micromirror device projection system according to a second embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0007]    Referring now to  FIG. 1  in the drawings, a high resolution DMD projection system according to an embodiment of the present invention is illustrated. While it is currently thought that a single DMD/DLP imager having resolution of about 2048×1080 (2K×1K) is insufficient for accurately reproducing an entire frame of motion picture image data onto a display surface, high resolution DMD projection system  100  advantageously utilizes a plurality of commercially available DMD/DLP imagers (each having resolution of about 2K×1K) to accomplish a total projected image resolution of about 4K×2K, a result acceptable by SMPTE standards. To accomplish this, the entire frame of a target display surface  104  is divided into four regions, an upper left region  106 , a lower left region  108 , an upper right region  110 , and a lower right region  112 . Region  106  is to be projected onto by DMD/DLP imager  114 , region  108  is to be projected onto by DMD/DLP imager  116 , region  110  is to be projected onto by DMD/DLP imager  118 , and region  112  is to be projected onto by DMD/DLP imager  120  such that each imager  114 ,  116 ,  118 ,  120  projects only a discrete portion of an entire frame of a motion picture image. In this embodiment, each imager  114 ,  116 ,  118 ,  120  is configured to project a substantially equal area of an entire frame of a motion picture image onto the display surface  104 . However, it will be appreciated that in alternative embodiments, the imagers may be configured to project unequal portions of a motion picture image while still providing a high resolution display. Each DMD/DLP imager  114 ,  116 ,  118 , and  120  is substantially similar to known single-imager type DMD/DLP imagers, but instead of each DMD/DLP imager  114 ,  116 ,  118 , and  120  having a color wheel filter (as known in the art), a single color wheel filter  122  is used. 
         [0008]    In operation, white light or full spectrum light is emitted from a light source  124  and is directed through the spinning color wheel filter  122 , possibly with guidance from an elliptical reflector  125 . Since each DMD/DLP imager  114 ,  116 ,  118 , and  120  must be supplied with light, the light exiting the spinning color wheel filter  122  is separated into four separate beams or channels of light (ideally identical in intensity and color) through the use of light beam splitting prisms. A first light beam splitting prism  126  splits the original light beam  128  into two new light beams  130  and  132 . Light beam  130  is directed from prism  126  into a second light beam splitting prism  134 , resulting in light beams  136  and  138 . Light beam  132  is directed from prism  126  into a third light beam splitting prism  140 , resulting in light beams  142  and  144 . Each of light beams  136 ,  138 ,  142 , and  144  are directed into and delivered through optical fibers (or equivalent thereof)  146  to total internal reflection lenses (TIR lenses)  148  associated with DMD/DLP imagers  114 ,  116 ,  118 , and  120 , respectively, such that each imager  114 ,  116 ,  118 , and  120  receives a single beam of light. TIR lenses are known in the art as being suitable for receiving light, directing the received light to a DMD/DLP imager, and finally outputting the light according to an image signal of the DMD/DLP imager. However, it will be appreciated that in an alternative embodiment, the TIR lenses may be replaced by field lenses. TIR lenses  148  are oriented to direct their output into an arrangement of reflective prisms  150  and optical blocks (or compensation optics)  152  so as to forward the four light beams  136 ,  138 ,  142 , and  144  (or channels of light) (as altered by DMD/DLP imagers  114 ,  116 ,  118 , and  120 ) into a projection optics system  154 . Projection optics system  154  ultimately directs the light beams  136 ,  138 ,  142 , and  144  onto regions  106 ,  108 ,  110 , and  112 , respectively, of the entire frame of the target display surface  104 . The input signals sent from display controllers of DMD/DLP imagers  114 ,  116 ,  118 , and  120  to the mirrors of the respective DMD/DLP imagers comprise only the data necessary to create the desired image to be projected onto the associated regions of display surface  104 . Further, the received beams of light are manipulated by imagers  114 ,  116 ,  118 , and  120  to carry motion picture image data corresponding to only a discrete portion of an entire motion picture image frame. It will be appreciated that in other embodiments of the present invention, more or fewer DLP imagers may be incorporated to achieve a higher or lower overall film screen resolution, respectively. 
         [0009]    Referring now to  FIG. 2  in the drawings, a high resolution DMD projection system according to a second embodiment of the present invention is illustrated. High resolution DMD projection system  200  is similar to system  100  in many ways including the fact that it advantageously utilizes a plurality of commercially available DMD/DLP imagers (each having resolution of about 2K×1K) to accomplish a total projected image resolution of about 4K×2K, a result acceptable by SMPTE standards. To accomplish this, the entire frame of a target display surface  204  is divided into four regions, an upper left region  206 , a lower left region  208 , an upper right region  210 , and a lower right region  212 . However, system  200  comprises four three-imager sets  214 ,  216 ,  218 , and  220  each comprising three DMD/DLP imagers  249  (the three-imager type DMD/DLP imagers being known in the art) instead of four single-imager type imagers (like  114 ,  116 ,  118 , and  120 ). Region  206  is to be projected onto by DMD/DLP imager set  214 , region  208  is to be projected onto by DMD/DLP imager set  216 , region  210  is to be projected onto by DMD/DLP imager set  218 , and region  212  is to be projected onto by DMD/DLP imager set  220 . Since each DMD/DLP imager of the three-DMD/DLP imager sets  214 ,  216 ,  218 ,  220  consistently manipulates a single color (red, green, or blue) there is no need for a color wheel filter (as needed in system  100 ). 
         [0010]    In operation, white light or full spectrum light is emitted from a light source  224  possibly with guidance from an elliptical reflector  225 . Since each DMD/DLP imager set  214 ,  216 ,  218 , and  220  must be supplied with light, the light exiting the light source  224  is separated into four channels of light (ideally identical in intensity and color) through the use of light beam splitting prisms as was similarly provided for in system  100 . A first light beam splitting prism  226  splits the original light beam  228  into two new light beams  230  and  232 . Light beam  230  is directed from prism  226  into a second light beam splitting prism  234 , resulting in light beams  236  and  238 . Light beam  232  is directed from prism  226  into a third light beam splitting prism  240 , resulting in light beams  242  and  244 . Each of light beams  236 ,  238 ,  242 , and  244  are directed into and delivered through optical fibers (or equivalent thereof)  246  to TIR lens/dichroic prism assemblies  248  associated with DMD/DLP imager sets  214 ,  216 ,  218 , and  220 , respectively. Assemblies  248  are known for splitting a light beam into three primary color light beams (red, green, and blue). TIR lens/dichroic prism assemblies  248  are known for receiving light, directing the received light to DMD/DLP imagers  249 , and finally outputting the light. However, it will be appreciated that in an alternative embodiment, the TIR lens portion of the TIR lens/dichroic prism assemblies may be replaced by field lenses. Assemblies  248  are oriented to direct their output into an arrangement of reflective prisms  250  and optical blocks (or compensation optics)  252  so as to forward the four light beams  236 ,  238 ,  242 , and  244  (or channels of light) (as altered by DMD/DLP imager sets  214 ,  216 ,  218 , and  220 ) into a projection optics system  254 . Projection optics system  254  ultimately directs the light beams  236 ,  238 ,  242 , and  244  onto regions  206 ,  208 ,  210 , and  212 , respectively, of the entire frame of the target display surface  204 . The input signals sent from display controllers of DMD/DLP imager sets  214 ,  216 ,  218 , and  220  to the mirrors of the respective DMD/DLP imagers comprise only the data necessary to create the desired image to be projected onto the associated regions of display surface  204 . It will be appreciated that in other embodiments of the present invention, more or fewer DLP imagers may be incorporated to achieve a higher or lower overall projected image resolution, respectively. By incorporating DMD/DLP imager sets  214 ,  216 ,  218 , and  220 , so-called rainbow effects (caused in part by the existence of a color wheel such as color wheel  122 ) are avoided and a higher level of color control is achieved. 
         [0011]    The foregoing illustrates only some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.