Projection autostereoscopic display and stereo screen

Abstract

A projection auto-stereoscopic display includes an image projector ( 100 ) and a stereo screen ( 200 ). The image projector ( 100 ) projects image. The image includes multiple viewing-zone pictures. The stereo screen ( 200 ) receives the image and reflects the image. The stereo screen ( 200 ) includes a linear polarizer ( 202 ), for receiving the image projected thereon and filtering the image in polarization. A first micro-retarder layer ( 204 ) is attached behind over the linear polarizer. A second micro-retarder layer ( 208 ) is disposed behind over the first micro-retarder layer ( 204 ). A reflection-type polarization preserved diffuser is disposed behind the second micro-retarder layer, for reflecting and diffusing an incident light into various directions.

1 . A projection autostereoscopic display, comprising:
 an image projector, to project an image out, wherein the image includes comprises multiple viewing-zone images; and   a stereo screen, receiving the image and reflecting the image back to an observing direction, wherein the stereo screen being an optical stack layer in a relative sequence from the projector comprises:
 a linear polarizer, for receiving the image incident thereon and filtering the image in polarization; 
 a first microretarder layer, attached behind over the linear polarizer, wherein the first microretarder layer has a plurality of column regions in a first retarding effect and a plurality of column regions in a second retarding effect, being alternatively configured; 
 a second microretarder layer, disposed behind over the first microretarder layer by a distance, wherein the second microretarder layer has a plurality of column regions in a third retarding effect and a plurality of column regions in a fourth retarding effect, being alternatively configured; and 
 a reflection-type polarization preserved diffuser, disposed behind over the second microretarder layer for reflecting and diffusing an incident light into various directions, wherein a polarization still preserved. 
   
     
     
         2 . The projection autostereoscopic display of  claim 1 , wherein the first microretarder layer is directly attached on the linear polarizer and the second microretarder layer is directly attached on the reflection-type polarization preserved diffuser. 
     
     
         3 . The projection autostereoscopic display of  claim 1 , wherein the column regions of the first microretarder layer are extending along a vertical direction of the stereo screen. 
     
     
         4 . The projection autostereoscopic display of  claim 3 , wherein the column regions of the second microretarder layer are extending along the vertical direction of the stereo screen but have a relatively horizontal shift to the column regions of the first microretarder layer. 
     
     
         5 . The projection autostereoscopic display of  claim 1 , wherein the column regions of the first microretarder layer are extending along a slant direction relative to a vertical direction of the stereo screen by an angle. 
     
     
         6 . The projection autostereoscopic display of  claim 3 , wherein the column regions of the second microretarder layer are extending along the slant direction but have a relatively horizontal shift to the column regions of the first microretarder layer. 
     
     
         7 . The projection autostereoscopic display of  claim 1 , wherein the image projector comprises a plurality of subsection projectors, each of the subsection projectors projecting a section image onto the stereo screen to compose the image in a full content. 
     
     
         8 . The projection autostereoscopic display of  claim 1 , wherein the reflection-type polarization preserved diffuser is directly disposed behind on the second microretarder layer. 
     
     
         9 . The projection autostereoscopic display of  claim 1 , wherein the stereo screen further comprises a phase compensator between the reflection-type polarization preserved diffuser and the first microretarder layer. 
     
     
         10 . The projection autostereoscopic display of  claim 9 , wherein the phase compensator comprises a reversed retardation plate. 
     
     
         11 . The projection autostereoscopic display of  claim 1 , wherein relative locations between the first microretarder layer and the second microretarder layer are set to produce a parallax barrier function for the stereo screen. 
     
     
         12 . The projection autostereoscopic display of  claim 1 , wherein the first to fourth retarding effects as respectively denoted by A-D satisfy conditions:
     A+C=±mπ, m= 0, 1, 2, 3, . . . ;       B+D=± ( n+ ½)π,  n= 0, 1, 2, . . . ; and
       A−B= ±(2 k+ 1)π,  k= 0, 1, 2, 3, . . . ;
     or       B+D=±mπ, m= 0, 1, 2, 3, . . . ;       A+C= ±( n+ ½)π,  n= 0, 1, 2, . . . ; and
       A−B= ±(2 k+ 1)π,  k= 0, 1, 2, 3, . . . .
   
     
     
         13 . The projection autostereoscopic display of  claim 1 , wherein the linear polarizer is a P polarization state or a S polarization state to block a portion of a reflected light in different polarization state as a parallax barrier. 
     
     
         14 . A stereo screen, used to receive an image and reflect the image back to an observing direction, the stereo screen being an optical stack layer comprising:
 a linear polarizer, for receiving the image incident thereon and filtering the image in polarization;   a first microretarder layer, attached over the linear polarizer, wherein the first microretarder layer has a plurality of column regions in a first retarding effect and a plurality of column regions in a second retarding effect, being alternatively configured;   a second microretarder layer, disposed over the first microretarder layer by a distance, wherein the second microretarder layer has a plurality of column regions in a third retarding effect and a plurality of column regions in a fourth retarding effect, being alternatively configured; and   a reflection-type polarization preserved diffuser, disposed over the second microretarder layer for reflecting and diffusing an incident light into various directions, wherein a polarization still preserved.   
     
     
         15 . The stereo screen of  claim 14 , wherein the first microretarder layer is directly attached on the linear polarizer and the second microretarder layer is directly attached on the reflection-type polarization preserved diffuser. 
     
     
         16 . The stereo screen of  claim 14 , wherein the column regions of the first microretarder layer are extending along a vertical direction of the stereo screen. 
     
     
         17 . The stereo screen of  claim 16 , wherein the column regions of the second microretarder layer are extending along the vertical direction of the stereo screen but have a relatively horizontal shift to the column regions of the first microretarder layer. 
     
     
         18 . The stereo screen of  claim 14 , wherein the column regions of the first microretarder layer are extending along a slant direction relative to a vertical direction of the stereo screen by an angle. 
     
     
         19 . The stereo screen of  claim 18 , wherein the column regions of the second microretarder layer are extending along the slant direction but have a relatively horizontal shift to the column regions of the first microretarder layer. 
     
     
         20 . The stereo screen of  claim 14 , wherein the reflection-type polarization preserved diffuser is directly disposed behind on the second microretarder layer. 
     
     
         21 . The stereo screen of  claim 14 , wherein the stereo screen further comprises a phase compensator between the reflection-type polarization preserved diffuser and the first microretarder layer. 
     
     
         22 . The stereo screen of  claim 21 , wherein the phase compensator comprises a reversed retardation plate. 
     
     
         23 . The stereo screen of  claim 14 , wherein relative locations between the first microretarder layer and the second microretarder layer are set to produce a parallax barrier function for the stereo screen. 
     
     
         24 . The stereo screen of  claim 14 , wherein depending on a projecting location of the image, widths of the column regions with the first retarding effect and the second retarding effect of the first microretarder layer are proportionally set in accordance with widths of the column regions with the third retarding effect and the fourth retarding effect of the second microretarder layer. 
     
     
         25 . The stereo screen of  claim 14 , wherein the first to fourth retarding effects as respectively denoted by A-D satisfy conditions:
     A+C=+±mπ, m= 0, 1, 2, 3, . . . ;       B+D=± ( n+ ½)π,  n= 0, 1, 2, . . . ; and
       A−B= ±(2 k+ 1)π,  k= 0, 1, 2, 3, . . . ;
     or       B+D=±mπ, m= 0, 1, 2, 3, . . . ;       A+C=± ( n+ ½)π,  n= 0, 1, 2, . . . ; and
       A−B=± (2 k+ 1)π, k=0, 1, 2, 3, . . . .
   
     
     
         26 . The stereo screen of  claim 14 , wherein the linear polarizer is a P polarization state or a S polarization state to block a portion of a reflected light in different polarization state as a parallax barrier.