Abstract:
Described is a rear projection television with reduced cabinet depth and method of manufacturing thereof. An anamorphic projection lens compresses an image and projects it along an optic path, where a cylindrical mirror expands and reflects the image within the optic path. The combination of compression and expansion facilitates in the design of a rear projection television with reduced cabinet depth.

Description:
TECHNICAL FIELD  
       [0001]     Disclosed embodiments relate to televisions, and more particularly to a rear projection television with reduced cabinet depth and height.  
       BACKGROUND  
       [0002]      FIG. 1  illustrates a prior-art rear projection television  100  having a light engine  102  situated near the bottom of the TV  100  along with a projection lens  104 . The light engine  102  may be refractive or reflective in nature and generally contains a light source, optical elements and lenses, and a spatial light modulator (such as a digital micromirror device (DMD)). The projection lens  104  may be integrated with the light engine  102 . The features and functions of SLMs and DMDs are further described in a commonly owned U.S. Pat. No. 6,038,056 entitled “Spatial light modulator having improved contrast ratio,” filed Jul. 16, 1999, which is incorporated herein by reference in its entirety for all purposes.  
         [0003]     An image may be generated by the light engine  102 , focused by the projection lens  104 , and projected onto a fold mirror  108  along a first optic axis  106 . The projected image is expanded along the first optic axis  106  as it is being projected from the projection lens  104  onto the fold mirror  108 . The fold mirror  108  may be curved or flat. The image is then reflected by the fold mirror  108  along a second optic axis  110 , and onto a TV screen  112 . As a result of the need to accommodate the light engine  102 , the projection lens  104 , and various optical components (not shown), as well as the length of the first and second optic axes  106 ,  110  within the projection TV  100 , conventionally there exists a certain cabinet depth  114  of about 13 to 16 inches from the TV screen  112  to the back of the television set  100 .  
       SUMMARY  
       [0004]     Described is a rear projection television with reduced cabinet depth and/or height and method of manufacturing thereof. An anamorphic projection lens compresses an image and projects it along a first optic path. A curved mirror then expands and reflects the image along a second optic path. The combination of compression and expansion facilitates in the design of a rear projection television with reduced cabinet depth and/or height. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  illustrates a cross-sectional view of a prior-art rear projection television;  
         [0006]      FIG. 2  illustrates a cross-sectional view of a rear projection television according to the present disclosure; and  
         [0007]      FIG. 3  illustrates a cross-sectional view of another embodiment of a rear projection television according to the present disclosure. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0008]      FIG. 2  illustrates a rear projection television  200  using the presently disclosed embodiments resulting in reduced cabinet depth  214  and/or reduced cabinet height  216 . As illustrated, a light engine  202  may be situated at the top of the TV  200  along with a projection lens  204 . The projection lens  204  may be integrated with the light engine  202 . Although the light engine  202  typically involves a spatial light modulator (SLM) (such as a digital micromirror device (DMD)), the light engine  202  may also be for liquid crystal type projection televisions  200 . The TV screen  212  may be a conventional rear projection screen.  
         [0009]     An image  220  is initially generated by the light engine  202  and focused by the projection lens  204 . The projection lens  204  is an anamorphic projection lens  204  that condenses or squeezes the image  222 . An anamorphic projection lens  204  can optically distort the image  220  in one or more dimensions. The distortion or compression may be vertical, horizontal, or combinations thereof. Additionally, other anamorphic optical elements (not shown) may be used to reduce the size of the image  222 . If the light engine  202  and the anamorphic projection lens  204  are integrated, then they can together operate to anamorphically project an image.  
         [0010]     The compressed or distorted image  222  is then projected onto a curved mirror  205  along a first optic axis  206 . Although the compression may distort the image  222 , it preserves the resolution of the image  220 . The curved mirror  205  may be a cylindrical mirror with reflective surfaces, shaped with power. Additionally, the curved mirror  205  may also be a non-planar mirror, a spherical mirror, or a mirror with a convex reflecting surface. Furthermore, the curved mirror  205  may be a cylindrical drum. In other embodiments, the mirrors  305  and  308  may be fresnel magnifiers or diffraction gratings, in which case the mirrors may be fabricated from planar substrates. The curved mirror  205 , due to its convex curvature, will expand the compressed image  222  to reproduce the original image  220 . In other words, the curved mirror  205  will return the compressed image  222  to its original size. The curved mirror  205  has similar anamorphic properties as that of the anamorphic projection lens  204 . Furthermore, the curvature of the curved mirror  205  may be designed to match the curvature of the anamorphic projection lens  204 . This configuration offers the ability to compress the depth of the projection TV cabinet. For example, in some embodiments, cabinet depths of twelve inches and less are enabled. Additionally, the height below the bottom of the screen, (also known as the chin height) may be reduced using this configuration.  
         [0011]     The re-established image  220  is then reflected from the curved mirror  205  onto a fold mirror  208  along a second optic axis  207 . The fold mirror  208  may be curved or flat (a curved embodiment is shown with reference to  FIG. 3 ). The fold mirror  208  will then take the restored image  220  and project it along a third optic axis  210 , and subsequently onto a TV screen  212 . Audiences can then view the restored image  220  projected on the TV screen  212 .  
         [0012]      FIG. 3  illustrates another embodiment of a rear projection television  300  in accordance with the present disclosure, resulting in reduced cabinet depth  314  and/or reduced cabinet height  316 . As shown, a light engine  202  may be situated at the top of the TV  300  along with a projection lens  204 . Rear projection TV  300  includes a first curved mirror  305  and a second curved mirror  308 , situated as shown in the figure. The TV screen  212  may be a conventional rear projection screen.  
         [0013]     The first curved mirror  305  in combination with the second curved mirror  308 , due to the convex curvature (or equivalent thereof) of both mirrors, operate to expand the compressed image  322  to reproduce the original image  330 . In other words, the first curved mirror  305  in combination with the second curved mirror  308  will return the compressed image  322  to its original size. The first curved mirror  305 , in combination with the second curved mirror  308 , has similar anamorphic properties as that of the anamorphic projection lens  204 . Furthermore, the curvatures of the first curved mirror  305  and second curved mirror  308  may be designed to match the curvature of the anamorphic projection lens  204 . This configuration offers the ability to further compress the height and depth of the projection TV cabinet. For example, in some embodiments, cabinet depths of twelve inches and less are enabled. Additionally, the height below the bottom of the screen, (also known as the chin height) may be further reduced using this configuration.  
         [0014]     Illustrating the operation of TV  300 , an image  330  is initially generated by the light engine  202  and focused by the projection lens  204 . The projection lens  204  is an anamorphic projection lens  204  that condenses or squeezes the image  322 . An anamorphic projection lens  204  can optically distort the image  330  in one or more dimensions. The distortion or compression may be vertical, horizontal, or combinations thereof. Additionally, other anamorphic optical elements (not shown) may be used to reduce the size of the image  322 . If the light engine  202  and the anamorphic projection lens  204  are integrated, then they can together operate to anamorphically project an image.  
         [0015]     The compressed or distorted image  322  is then projected onto a first curved mirror  305  along a first optic axis  306 . Although the compression may distort the image  322 , it preserves the resolution of the partially re-established image  320 . The curved mirrors  305  and  308  may be a cylindrical mirrors with reflective surfaces. Additionally or alternatively, the curved mirrors  305  and  308  may be non-planar mirrors, spherical mirrors, mirrors with a convex reflecting surface, cylindrical drums, or a combination thereof. In other embodiments, the mirrors  305  and  308  may be fresnel magnifiers or diffraction gratings, in which case the mirrors may be fabricated from planar substrates.  
         [0016]     The partially re-established image  320  is then reflected from the first curved mirror  305  onto a second curved mirror  308  along a second optic axis  207 . As previously discussed, second curved mirror  308  may be curved or of a construction that provides similar power properties of a curved mirror. The second curved mirror  308  will then take the partially re-established image  320  and reflect it along a third optic axis  310 , and subsequently onto a TV screen  212  to create restored image  330 . Audiences can then view the restored image  330  projected on the TV screen  212 .  
         [0017]     It will be appreciated by those of ordinary skill in the art that the invention can be embodied in other specific forms without departing from the spirit or essential character thereof. For example, as a result of the distorting and recovering the image, there may also be a reduction in chin height, or the spacing between the bottom of the TV screen  212  and the bottom of the television set  200 . In another example, the overall configuration may also be inverted such that the light engine  202  may be situated at the bottom of the cabinet. Other variations may include positioning the light engine at either side of the cabinet. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than the foregoing description, and all changes that come within the meaning and ranges of equivalents thereof are intended to be embraced therein.  
         [0018]     Additionally, the section headings herein are provided for consistency with the suggestions under 37 C.F.R. § 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically and by way of example, although the headings refer to a “Technical Field,” the claims should not be limited by the language chosen under this heading to describe the so-called technical field. Further, a description of a technology in the “Background” is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” to be considered as a characterization of the invention(s) set forth in the claims found herein. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty claimed in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims associated with this disclosure, and the claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of the claims shall be considered on their own merits in light of the specification, but should not be constrained by the headings set forth herein.