Autostereoscopic projection system

Abstract

The invention relates to an autostereoscopic projection arrangement, comprising at least one projector ( 4 ) and at least one filter array (F 1 , F 2 ), which has a multitude of filter elements arranged in columns and rows, in which arrangement bits of partial information from views of a scene or object are projected by the projector/the projectors ( 4 ) onto a projection screen ( 3 ), where these bits of partial information are rendered on image rendering elements and, having passed one or several of the filter arrays (F 1 , F 2 ), are made visible to at least one observer ( 5 ), and in which, as regards the propagation direction of the bits of partial information, the image rendering elements correspond with correlated filter elements in such a way that an observer ( 5 ) will see predominantly bits of partial information from a first selection of views with one eye and predominantly bits of partial information from a second selection of views with the other eye, and thus will have a spatial impression.

1 . An autostereoscopic projection arrangement, comprising:
 at least one projector arranged for back projection of bits of partial image information from at least two views of a scene or object onto a holographic screen, in which   the holographic screen has a multitude of holographic optical elements (HOEs) that are arranged in a grid of columns and/or rows, and   light incident from the projector is optically imaged by an optical imaging system, onto the holographic screen such that the multitude of HOEs define a multitude of propagation directions, so that an observer will see predominantly bits of partial information of a first selection of views with one eye and predominantly bits of partial information of a second selection of views with the other eye, and thus will perceive a spatial impression from a multitude of viewing positions.   
     
     
         2 . The autostereoscopic projection arrangement according to  claim 1 , in which
 each HOE displays the light incident from the at least one projector by at least one of the following optical imaging types selected from a group consisting of:   a) imaging by a lens,   b) imaging by a cylindrical lens arranged vertically or obliquely to the vertical,   c) diffusely transparent or translucent imaging, with subsequent imaging by a lens,   d) imaging by a prism,   e) diffusely transparent or translucent imaging, with subsequent imaging by means of a prism,   f) imaging through a polygonal polarizing filter stepped neutral density filter wavelength filter or a combination of the foregoing, with a wavelength filter transmitting light of a specified wavelength or one or several specified wavelength ranges,   g) imaging by an optical flat,   h) imaging by diffraction.   
     
     
         3 . The autostereoscopic projection arrangement according to  claim 2 , comprising
 eight projectors, each of which renders one view of the scene or object, and arranged on a circular arc, with the imaging beam paths of the projectors being directed onto the rear side of the holographic screen and the optical axes of these imaging beam paths including angles of about α˜8.6°, in which   the HOEs are spaced from each other on the holographic screen by approximately 0.1 mm in both coordinates, and   the propagation directions of the light radiated by the holographic screen and carrying bits of partial information of the views include angles of about β˜0.83°, in which   the multitude of viewing positions are established at a distance of approximately 4.5 m from the holographic screen.   
     
     
         4 . The autostereoscopic projection arrangement according to  claim 2 , comprising
 four projectors, each of which renders two views of the scene or object, and arranged on a circular arc, with the imaging beam paths of the projectors being directed onto the rear side of the holographic screen and the optical axes of these imaging beam paths including angles of about α˜17.2°, in which   the HOEs are spaced from each other on the holographic screen by approximately 0.1 mm in both coordinates, and   the propagation directions of the light radiated by the holographic screen and carrying bits of partial information of the views include angles of about β˜17.2°, in which   the multitude of viewing positions are established at a distance of approximately 4.5 m from the holographic screen.   
     
     
         5 . The autostereoscopic projection arrangement according to  claim 1  further comprising:
 at least one projector arranged for the front-side projection of bits of partial image information from at least two views of a scene or object onto a holographic screen, in which   each HOE displays the light incident from at least one projector by at least one of the optical imaging types or combinations of imaging types selected from a group consisting of:   a) imaging by a concave mirror,   b) imaging by a convex mirror,   c) imaging by a cylindrical concave mirror arranged vertically or obliquely to the vertical,   d) diffuse reflection, with subsequent imaging of a concave or convex mirror, preferably a cylindrical concave mirror arranged vertically or obliquely to the vertical,   e) imaging by means of a doublet or triplet of corner reflector mirrors,   f) diffuse reflection, with subsequent imaging by means of a doublet or triplet of mirrors,   g) imaging through a polygonal polarizing filter, a stepped neutral density filter, a wavelength filter or a combination of the foregoing, with a wavelength filter transmitting light of a specified wavelength or one or several specified wavelength ranges,   h) diffuse reflection, with subsequent imaging by an optical flat,   i) diffuse reflection, with subsequent imaging by a prism,   j) imaging by diffraction.   
     
     
         6 . The autostereoscopic projection arrangement according to  claim 1  in which at least two of the HOEs on the holographic screen deviate from each other in their outer dimensions, their outer shape, or both. 
     
     
         7 . The autostereoscopic projection arrangement according to  claim 1  in which the relative positions of area centroids of at least two of the HOEs on the holographic screen deviate from each other by an offset equal to a non-integral multiple of the width, height of one of the said HOEs, or both. 
     
     
         8 . The autostereoscopic projection arrangement according to  claim 1 , in which at least one of the HOE displays light of different wavelength ranges in pairs of disjoint directions. 
     
     
         9 . Autostereoscopic projection arrangement according to  claim 1 , in which the grid in which the HOEs are arranged on the holographic screen is an orthogonal grid. 
     
     
         10 . The autostereoscopic projection arrangement according to  claim 1 , in which the grid in which the HOEs are arranged on the holographic screen is a non-orthogonal grid, in which the rows intersect the columns at an angle that is not equal to 90 degrees. 
     
     
         11 . The autostereoscopic projection arrangement according to  claim 1 , in which at least one HOE simultaneously defines at least two light propagation directions for light from at least one direction of incidence. 
     
     
         12 . The autostereoscopic projection arrangement according to  claim 1 , comprising
 at least two projectors, with each projector projecting either bits of partial image information of only one view of a scene or object, or simultaneously bits of partial image information of at least two views of a scene or object,   at least one projector projects bits of partial image information of at least one view of the scene or object at certain points in time only, at a specified frequency between about 10 Hz and about 60 Hz,   the light of at least of one projector is displayed in such a way that it can be seen from the front side within a solid angle that is at least about 0.37π*sr, so that the light of the said projector is seen by the observer as an essentially two-dimensional image, in which   each of the projectors comprises at least one DMD chip, one LCD component, one CRT or one laser.   
     
     
         13 . The autostereoscopic projection arrangement according to  claim 1 , in which there is, in a viewing space, at least one viewing position for an observer's eye into which the holographic screen does not radiate essentially any of light projected by the projectors. 
     
     
         14 . The autostereoscopic projection arrangement according to  claim 1 , further comprising a color mask in a beam path between the projector and the projection screen, the color mask directing different color shares, the colors red, green and blue, to different subpixels belonging to a pixel of the projection screen, such that the subpixels, in addition to the pure colors red, green and blue, also render mixed colors, so that a greater number of colors per subpixel can be rendered and the resolution of the projection screen is thus increased. 
     
     
         15 . The autostereoscopic projection arrangement according to  claim 14 , characterized in that the width I new  of the colors that can be rendered per pixel results from 
       
         
           
             
               
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         wherein I is the size of one subpixel and n the number of subpixels per pixel, or in that the number p new  of views renderable per pixel increases according to the function 
       
       
         
           
             
               
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         wherein n is the number of subpixels per pixel, and p the number of different views of the scene or object. 
       
     
     
         16 . The autostereoscopic projection arrangement according to  claim 14 , in which n=3 and p=8. 
     
     
         17 . A method of manufacturing a holographic screen for use in an autostereoscopic projection arrangement, comprising the steps of:
 a) manufacturing a first optical arrangement containing a multitude of the optical components permitting optical imaging types or combinations of imaging types selected from a group consisting of:   imaging by a concave mirror,   imaging by a convex mirror,   imaging by a cylindrical concave mirror arranged vertically or obliquely to the vertical,   diffuse reflection, with subsequent imaging of a concave or convex mirror, preferably a cylindrical concave mirror arranged vertically or obliquely to the vertical,   imaging by means of a doublet or triplet of corner reflector mirrors,   diffuse reflection, with subsequent imaging by means of a doublet or triplet of mirrors,   imaging through a polygonal polarizing filter, a stepped neutral density filter, a wavelength filter or a combination of the foregoing, with a wavelength filter transmitting light of a specified wavelength or one or several specified wavelength ranges,   diffuse reflection, with subsequent imaging by an optical flat,   diffuse reflection, with subsequent imaging by a prism,   imaging by diffraction,   imaging by a lens,   imaging by a cylindrical lens arranged vertically or obliquely to the vertical,   diffusely transparent or translucent imaging, with subsequent imaging by a lens,   imaging by a prism,   diffusely transparent or translucent imaging, with subsequent imaging by means of a prism,   imaging through a polygonal polarizing filter stepped neutral density filter wavelength filter or a combination of the foregoing, with a wavelength filter transmitting light of a specified wavelength or one or several specified wavelength ranges,   imaging by an optical flat,   b) positioning of an undeveloped holographic screen in the vicinity of the first optical arrangement;   c) exposing the holographic screen to one or several coherent light sources, in which the holographic screen is struck by a reference beam coming directly from the light source and an object beam which, also coming from the light source, has passed the first optical arrangement.   d) developing the holographic screen.   
     
     
         18 . The method according to  claim 17  further comprising the step of repeating step “c” several times. 
     
     
         19 . The method according to  claim 17  further comprising the steps of repositioning the light source relative to the optical arrangement and repeating step “c”. 
     
     
         20 . The method according to  claim 17  further comprising the steps of substituting a second optical arrangement for the first optical arrangement and repeating step “c”. 
     
     
         21 . A method of manufacturing a holographic screen for use in an autostereoscopic projection arrangement, comprising the steps of:
 a) selecting a multitude of optical components providing the optical imaging types or combinations thereof, selected from a group consisting of:   imaging by a concave mirror,   imaging by a convex mirror,   imaging by a cylindrical concave mirror arranged vertically or obliquely to the vertical,   diffuse reflection, with subsequent imaging of a concave or convex mirror, preferably a cylindrical concave mirror arranged vertically or obliquely to the vertical,   imaging by means of a doublet or triplet of corner reflector mirrors,   diffuse reflection, with subsequent imaging by means of a doublet or triplet of mirrors,   imaging through a polygonal polarizing filter, a stepped neutral density filter, a wavelength filter or a combination of the foregoing, with a wavelength filter transmitting light of a specified wavelength or one or several specified wavelength ranges,   diffuse reflection, with subsequent imaging by an optical flat,   diffuse reflection, with subsequent imaging by a prism,   imaging by diffraction,   imaging by a lens,   imaging by a cylindrical lens arranged vertically or obliquely to the vertical,   diffusely transparent or translucent imaging, with subsequent imaging by a lens,   imaging by a prism,   diffusely transparent or translucent imaging, with subsequent imaging by means of a prism,   imaging through a polygonal polarizing filter stepped neutral density filter wavelength filter or a combination of the foregoing, with a wavelength filter transmitting light of a specified wavelength or one or several specified wavelength ranges,   imaging by an optical flat,   b) arranging the optical components in a grid of rows and/or columns;   c) computing respective holographic interference patterns for the imaging types or combinations;   d) exposing the holographic screen to one or several coherent light sources such that the computed holographic interference pattern is written onto the holographic screen;   e) developing the holographic screen.   
     
     
         22 . An autostereoscopic projection arrangement comprising:
 at least one projector that is suitable for the projection of at least one image containing image information from a number of n views (n≧2) of a scene or object; and   A projection screen containing a multitude of reflectors arranged in afield mode and receiving light from the projector, in which the reflectors reflect the light in different directions in space so that an observer looking at the projection screen will see predominantly information from a first selection of the n (n≧2) views with a first eye and predominantly information from a second selection of views with a second eye, such that an observer will have a spatial impression of the scene or object.   
     
     
         23 . The autostereoscopic projection arrangement as claimed in  claim 22 , further comprising a second projector and in which at least one reflector of the multitude of reflectors simultaneously receives light from both the first projector and the second projector, and in which the at least one reflector reflect the light received from the first and second projectors in different directions in space. 
     
     
         24 . The autostereoscopic projection arrangement as claimed in  claim 22 , further comprising further additional projection screens and in which the first and the further additional projection screens are arranged and positioned substantially adjacent one another in a modular design so as to jointly form a projection surface, the diagonal of which is greater than the diagonal of a single projection screen. 
     
     
         25 . The autostereoscopic projection arrangement as claimed in  claim 24 , further comprising a second projector and in which each of the first and second projectors project onto the projection surface partial information from views of the scene or object.