Projection display system

Abstract

In one embodiment, a projection screen includes a diffuse reflecting polarizer that diffusively reflects light polarized in a first direction and transmits light polarized in a second direction. The projection screen may also include a second polarizer adjacent a back side of the diffuse reflecting polarizer, wherein the second polarizer is oriented to transmit light polarized in the second direction. The projection screen may appear substantially diffuse when viewed from a front side and substantially transparent when viewed from a back side.

1 . An apparatus comprising: 
 a diffuse reflecting polarizer that diffusively reflects light polarized in a first direction and transmits light polarized in a second direction; and    a second polarizer adjacent a back side of the diffuse reflecting polarizer, wherein the second polarizer is oriented to transmit light polarized in the second direction.    
     
     
         2 . The apparatus of  claim 1 , wherein the second polarizer includes a reflective polarizer that reflects light polarized in the first direction.  
     
     
         3 . The apparatus of  claim 1 , wherein the second polarizer includes an absorption polarizer that absorbs light polarized in the first direction.  
     
     
         4 . The apparatus of  claim 1 , wherein the second polarizer includes a non-diffuse polarizer.  
     
     
         5 . The apparatus of  claim 1 ,wherein the first direction is substantially perpendicular to the second direction.  
     
     
         6 . The apparatus of  claim 1 , wherein the apparatus appears substantially transparent when viewed from a back side of the apparatus corresponding to a light incident side of the second polarizer and appears substantially diffuse when viewed from a front side of the apparatus corresponding to a light incident side of the diffuse reflecting polarizer.  
     
     
         7 . The apparatus of  claim 6 , wherein the apparatus transmits at least 20% of randomly polarized light incident the front side of the apparatus.  
     
     
         8 . The apparatus of  claim 7 , wherein the apparatus transmits at least 35% of randomly polarized light incident the front side of the apparatus.  
     
     
         9 . The apparatus of  claim 7 , wherein the apparatus transmits approximately 50% of randomly polarized light incident the front side of the apparatus.  
     
     
         10 . The apparatus of  claim 6 , wherein the apparatus diffusely reflects greater than approximately 20% of randomly polarized light incident the front side of the apparatus.  
     
     
         11 . The apparatus of  claim 10 , wherein the apparatus diffusely reflects greater than approximately 35% of randomly polarized light incident the front side of the apparatus.  
     
     
         12 . The apparatus of  claim 10 , wherein the apparatus diffusely reflects approximately 50% of randomly polarized light incident the front side of the apparatus.  
     
     
         13 . The apparatus of  claim 1 , wherein the apparatus reflects greater than approximately 70% of light polarized in the first direction incident the diffuse reflecting polarizer.  
     
     
         14 . The apparatus of  claim 13 , wherein the apparatus reflects greater than approximately 80% of light polarized in the first direction incident the diffuse reflecting polarizer.  
     
     
         15 . The apparatus of  claim 13 , wherein the apparatus reflects greater than approximately 90% of light polarized in the first direction incident the diffuse reflecting polarizer.  
     
     
         16 . The apparatus of  claim 1 , further comprising a glare-suppressing element adjacent a front side of the diffuse reflecting polarizer to suppress glare.  
     
     
         17 . A system comprising: 
 a multi-color transmissive projector that emits light in which all colors are substantially polarized in a common direction; and    a diffuse reflecting projection screen that reflects light polarized in a same direction as the light emitted from the projector, and transmits light polarized in a different direction as the light emitted from the projector.    
     
     
         18 . The system of  claim 17 , wherein the diffuse reflecting projection screen comprises a diffuse reflecting polarizer that diffusively reflects light polarized in a first direction and transmits light polarized in a second direction.  
     
     
         19 . The system of  claim 18 , wherein the diffuse reflecting projection screen further includes a second polarizer adjacent a back side of the diffuse reflecting polarizer, wherein the second polarizer is oriented to transmit light polarized in the second direction.  
     
     
         20 . The system of  claim 19 , wherein the second polarizer comprises a polarizer selected from the following group: an absorbing polarizer and a reflecting polarizer.  
     
     
         21 . The system of  claim 17 , wherein the diffuse reflecting projection screen is a two-sided screen comprising: 
 a first diffuse reflecting polarizer that diffusely reflects light polarized in a first direction and transmits light polarized in a second direction    a second diffuse reflecting polarizer that reflects light polarized in the first direction and transmits light polarized in the second direction; and    a third polarizer, between the first and second diffuse reflecting polarizers.    
     
     
         23 . The system of  claim 21 , further including a second projector to project an image on a second side of the projection screen, wherein the second side is a light incident side of the second diffuse reflecting polarizer.  
     
     
         24 . The system of  claim 21 , wherein the projector is a dual image projector that simultaneously projects an image onto both sides of the screen.  
     
     
         25 . The system of  claim 17 , wherein the multi-color transmissive projector is a liquid crystal display projector.  
     
     
         26 . The system of  claim 17 , wherein the projector includes a rotator to rotate polarization of at least some of the light emitted from the projector such that all the colors are polarized in the common direction.  
     
     
         27 . The system of  claim 17 , wherein the projector includes a color combiner that combines the colors.  
     
     
         28 . The system of  claim 17 , further including a mirror to reflect light emitted from the projector onto the projection screen.  
     
     
         29 . A system comprising: 
 a multi-color transmissive projector that emits light;    a rotator to rotate polarization of at least some of the light emitted from the projector such that all colors of light are polarized in a common direction; and    a projection screen onto which the light emitted from the projector is diffusely reflected, wherein the projection screen appears substantially diffuse when observed from one side of the screen and appears substantially transparent when observed from an opposite side of the screen.    
     
     
         30 . The system of  claim 29 , wherein the projection screen comprises: 
 a diffuse reflecting polarizer that diffusively reflects light polarized in a first direction and transmits light polarized in a second direction; and    a second polarizer adjacent a back side of the diffuse reflecting polarizer, wherein the polarizer is oriented to transmit light polarized in the second direction.    
     
     
         31 . A method comprising: 
 combining multiple colors of light such that all of the colors of light are substantially polarized in a first direction; and    projecting the combined colored light onto a display screen that diffusely reflects light polarized in the first direction and transmits light polarized in a second direction.    
     
     
         32 . A method comprising: 
 combining multiple colors of light such that all of the colors of light are substantially polarized in a first direction; and    projecting the combined colored light onto a display screen that reflects light polarized in the first direction and absorb light polarized in the second direction.    
     
     
         33 . An apparatus comprising: 
 a diffuse reflecting polarizer that diffusively reflects light polarized in a first direction and transmits light polarized in a second direction; and    a reflecting polarizer adjacent a back side of the diffuse reflecting polarizer, wherein the reflective polarizer is oriented to reflect light polarized in the first direction and transmit light polarized in the second direction such that the apparatus appears substantially transparent when viewed from a back side of the apparatus corresponding to a light incident side of the reflecting polarizer and appears substantially diffuse when viewed from a front side of the apparatus corresponding to a light incident side of the diffuse reflecting polarizer.    
     
     
         34 . An apparatus comprising: 
 a diffuse reflecting polarizer that diffusively reflects light polarized in a first direction and transmits light polarized in a second direction; and    an absorbing polarizer adjacent a back side of the diffuse reflecting polarizer, wherein the absorbing polarizer is oriented to absorb light polarized in the first direction and transmit light polarized in the second direction such that the apparatus appears substantially transparent when viewed from a back side of the apparatus corresponding to a light incident side of the absorbing polarizer and appears substantially diffuse when viewed from a front side of the apparatus corresponding to a light incident side of the diffuse reflecting polarizer.    
     
     
         35 . An apparatus comprising: 
 a means for combining multiple colors of light such that all of the colors of light are substantially polarized in a common direction;    a means for projecting the combined colors of light; and    a means for diffusely reflecting the projected combined colors of light, wherein the means for diffusely reflecting substantially transmits light that is not polarized in the common direction.