Patent Document

CROSS REFERENCE TO RELATED APPLICATION 
     This application claims filing-date priority to U.S. Provisional Patent Application Ser. No. 60/995,802, filed Sep. 27, 2007, for “Short-Wavelength, Long-Depth-of-Field, Folded-Image Projection”. The entire disclosure content of that prior-filed provisional application is hereby incorporated herein by reference. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     This invention relates to a peripheral projection system. More particularly, it relates to a peripheral projection system which is generally upright, and which utilizes a high-resolution laser color projection source. The color projection source may comprise three lasers with appropriate output optics. The peripheral projection system may include the projection source, or alternatively it may be coupled to receive the output of the projection source through the periphery of the peripheral projection system. The output of the color projection source, or “image” is thereafter subjected to a unique optical path structure which vertically folds the image several times within a thin region of space, referred to herein as an image-projection depth region, that lies behind a display screen for displaying the image. The optical path structure includes a “downstream” turning screen which, through an optical diffuser structure, directs the image toward the rear side of the display screen. The nominal plane of the image-projection depth region may substantially parallel that of the display screen. 
     The invention further comprises what is referred to herein as a system geometry structure—including a periphery including a supporting frame structure—on which components are mounted. The supporting frame structure defines a large ratio of diagonal screen measure to depth (or “depth ratio”) of preferably at least 10:1. 
     The invention thus fits well into that realm of current screen-display system technology which takes aim at providing large-surface-area, but extremely thin, image-display systems of the types typically used, for example, in television and computer-display applications. 
     The various features and advantages which are offered by the invention, including those just mentioned above, and beyond, will become more fully appreciated as the detailed description of the invention which follows below is read in conjunction with the accompanying drawing figures. With respect to these drawing figures, it should be noted at the outset that the herein-illustrated, cooperative components of the system of the invention, and the organization of those components, are not necessarily drawn to scale. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a very simplified, isometric view illustrating the front of a peripheral projection system which has been constructed in accordance with a preferred and best-mode embodiment of the present invention. 
         FIG. 2  is a fragmentary, exploded, isometric view, generally taken from the same point of view which is employed in  FIG. 1 , illustrating just certain ones of the components employed in the display system of  FIG. 1 . 
         FIG. 3  is a rear isometric view, with covering structure removed, illustrating the rear side of an optical path structure which is employed in the peripheral projection system. 
         FIG. 4  is a fragmentary side elevation of the system of the invention, illustrating further the optical path structure employed therein, as well as showing schematically several optical paths along which a projected image travels and is folded vertically en route from a projection source to the rear side of the peripheral projection system&#39;s display screen. 
         FIG. 5  is a fragmentary cross-section of a portion of a turning screen which is employed in the optical path structure of the invention. 
         FIG. 6  is a fragmentary cross-section of a portion of a diffuser structure which is employed in the peripheral projection system intermediate the turning screen of  FIG. 5 , and the rear side of the display screen. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to all of the drawing figures, indicated generally at  10  is an upright peripheral projection display system which is constructed in accordance with a preferred and best mode embodiment of the present invention. System  10  includes a generally planar image display screen  12 , having a rear side  12   a  and a diagonal measure shown at D in  FIG. 1 . The nominal plane of the display screen  12  is shown generally at  12   b . In an embodiment of system  10 , the system  10  also includes a projection source  14  mounted to the bottom  13   a  of the system  10 . The projection source  14  may alternatively be mounted on any of the bottom  13   a , top  13   c , or sides  13   b ,  13   d , all of which make up the periphery of the system  10 . In another embodiment, the projection source  14  may be external to the system  10 , and in such embodiment the system  10  includes an interface on the periphery of the system  10  to accept the image which is output from the projection source. The projection source  14  may include a laser-based projection source. The system  10  further includes a generally planar image projection depth region  16  having an image projection depth W (seen especially well in  FIG. 4 ), an optical path structure  18  which is disposed operatively intermediate to source  14  and the rear side of screen  12 , and a system geometry structure, including a frame  20 , on which the components in the system  10  are suitably mounted. The nominal plane of region  16  is shown generally at  16   a.    
     As expressed and illustrated herein, system geometry structure  18  importantly defines, in system  10 , a relatively thin optical path structure. The thin optical path structure allows for a depth ratio of diagonal dimension D to image-projection depth W which is at least as large as 10:1. As an example, dimension D herein may be about 52-inches, and dimension W may be about 4-5-inches. As a consequence of depth ratio, system  10  offers a very large image-viewing surface in an otherwise very thin image projection optical structure. 
     Individually, the several components just mentioned as being included in the system  10  may be (and are herein) entirely conventional in construction, but their cooperative organization, as presented herein in accordance with the present invention, is unique. 
     In the embodiment of system  10  illustrated in the drawings, wherein the source  14  is coupled to the bottom  13   a  of the system, optical path structure  18  includes (a) an upper first bounce mirror  22 , (b) a lower second bounce mirror  24 , (c) an upperthird bounce mirror  26 , (d) a turning screen  28 , (e) a clear glass plate  30 , and (f) a planar diffuser structure  32 . In one embodiment of the invention, the upper first bounce mirror  22  and upper third bounce mirror  26  are cylindrical, and the lower second bounce mirror  24  is flat. Individually, these components are conventional in construction, and accordingly, only a few, representative details of a few of them are presented herein. 
     Mirrors  22 ,  24 ,  26  may be referred to herein collectively as the cascade substructure or image reflection/expansion structure, or as the upstream portion of optical path structure  18 . Turning screen  28  is referred to herein as being the downstream portion of optical path structure  18 . 
     In  FIG. 4  in the drawings, optical path structure  18  defines a vertically folded optical path for the “optical flow” of an image projected from source  14  to the rear side,  12   a , in display screen  12 . This optical path includes, essentially, four portions which are shown in  FIG. 4  at  18   a ,  18   b ,  18   c  and  18   d . Path portion  18   a  lies between source  14  and mirror  22 . Path portion  18   b  lies between mirror  22  and mirror  24 . Path portion  18   c  lies between mirror  24  and mirror  26 . And finally, optical path portion  18   d  lies between mirror  26  and turning screen  28 . As such, when an image is input to the optical path structure  18  from the source  14 , wherein the image is input on the bottom  13   a  of the system  10 , the image is folded a first time by reflection off of mirror  22 , a second time by reflection off of mirror  24 , and a third time by reflection off of mirror  26 . Thus, the optical path  18  of the invention folds the image multiple times within a relatively thin image-projection depth region  16 . 
     As can be seen in  FIG. 4 , the just-described optical path portions lie at shallow angles, e.g. angles of about 10-degrees relative to one another. Path portion  18   a , with system  10  occupying generally an upright, or vertical plane, extends in a vertical plane between source  14  and first-bounce mirror  22 , which mirror in one embodiment has a cylindrical, curved-surface radius in the range of about 75-200-millimeters. As can be seen in  FIG. 3 , path portion  18   a  experiences a slight lateral expansion en route from source  14  to mirror  22 . 
     Path portion  18   b  extends downwardly from mirror  22  to second-bounce mirror  24 , expanding laterally along the way generally in a plane which is inclined from the mirror  22  toward rear side  12   a  in screen  12  at a shallow angle, for example, an angle of about 10 degrees. 
     Optical path portion  18   c  extends upwardly in a generally vertical plane from mirror  24  to third bounce mirror  26  which is located near the top of system  10 . The image projection “information” contained in the image within path portion  18   c  continues to expand laterally as it is reflected from mirror  24  to mirror  26 . In an embodiment, mirror  26  has a cylindrical, curved-surface radius lying generally within the range of about 3000-5000-millimeters. 
     Optical path portion  18   d  extends downwardly, at a downwardly and forwardly glancing shallow angle of, e.g. 10 degrees, from mirror  26  to impinge on what is the rear surface of turning screen  28 .  FIG. 5 , in a much larger scale than that which is employed in  FIG. 4 , further illustrates impingement of path portion  18   d  onto the mentioned rear surface of turning screen  28 . 
     Turning attention now to  FIG. 5  in the drawings, here what is illustrated is a fragmentary, cross-sectional view of a portion of turning screen  28 . In the particular preferred embodiment of system in  10  which is illustrated and described herein, turning screen  28  generally has the configuration which is shown in  FIG. 5 . Those skilled in the art will certainly recognize that different system geometries may dictate a different structure for a turning screen. 
     Within  FIG. 5 , two angles and four dimensions are marked. These angles and dimensions are simply illustrative of one “geometry” which may be used in a turning screen. Angle α 1  is about 50-degrees, angle α 2  is about 10-degrees, dimension  28   a  is about 0.11-millimeters, dimension  28   b  is about 0.05-millimeters, dimension  28   c  is about 0.1-millimeters, and dimension  28   d  lies in the range of about 0.5-1-millimeters. With respect to the particular turning screen  28  which is illustrated herein, dimension  28   d  is about 1-millimeters. 
     Self-explanatory arrows in  FIG. 5  illustrate the relevant optical paths which are associated with screen  28 . Optical information emerging from the right side of screen  28  in the  FIG. 5  flows through previously mentioned glass plate  30  toward what is the rear side of previously mentioned diffuser structure  32 . 
       FIG. 6  in the drawings furnishes an enlarged, fragmentary, cross-sectional view of a portion of diffuser structure  32 . Diffuser structure  32  includes a clear substrate  34  possessing a plurality of isosceles triangular horizontally extending front surface grooves  36  which are outwardly surface-coated with aluminum particulate material  38 . Each of these grooves is appropriately filled with a darkened, black filler material which is shown generally at one location only in  FIG. 6  at  40 . 
     In  FIG. 6 , angle α 3  is about 40-degrees, dimension  32   a  is about 0.12-millimeters, dimension  32   b  is about 0.08-millimeters, dimension  32   c  is about 0.16-millimeters, and dimension  32   d  is a dimension which lies generally within the range of about 0.5-1-millimeters. With respect to the particular diffuser structure  32  which is illustrated herein, dimension  32   d  is about 1-millimeters. 
     Those having skill in the art will appreciate that there are various vehicles by which the system described herein can be effected, and that the preferred vehicle will vary with the context in which the processes are deployed. 
     For example, while the embodiment of the invention herein describes a three-mirror structure of optical path  18 , one can appreciate that one may employ more mirrors in implementing the structure of the invention. Furthermore, while the peripheral projection system described herein illustrates the source being coupled to the bottom of the system and the first bounce mirror being coupled to the top of the system, this configuration could be rotated in an implementation of the invention. 
     The foregoing described aspects depict different components contained within, or connected with, different other components. It is to be understood that such depicted system architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected”, or “operably coupled”, to each other to achieve the desired functionality.

Technology Category: 3