Polarized Projection Display

Abstract

A projection display system includes (1) a first polarizer, (2) a transparent screen, (3) a second polarizer on the transparent screen, and (4) a projector for projecting an image through the first polarizer and onto the transparent screen. The first and the second polarizers have different polarization directions so that the image is visible from a first side of the transparent screen and invisible from a second side of the transparent screen.

1 . An automobile comprising: 
 a projection display system, comprising: 
 a first polarizer having a first polarization direction;  
 a transparent screen;  
 second polarizer on the transparent screen, the second polarizer having a second polarization direction different from the first polarization direction; and  
 a projector for projecting an image through the first polarizer and onto the second polarizer, wherein the image is visible from a first side of the transparent screen to a rear passenger and invisible from a second side of the transparent screen to a driver so the driver can look through the transparent screen and out of a rear windshield of the automobile.  
   
   
   
       2 . (canceled)  
   
   
       3 . The system of  claim 1 , wherein the projector and the first polarizer are located on the first side of the transparent screen.  
   
   
       4 . The system of  claim 1 , further comprising a mirror for reflecting the image from the projector onto the transparent screen, wherein the projector is located on the second side of the transparent screen and the mirror is located on the first side of the transparent screen.  
   
   
       5 . The system of  claim 1 , wherein the first polarizer is located on a lens of the projector.  
   
   
       6 . A method for projecting an image on a transparent screen in an automobile so the image is visible from a first side of the transparent screen to a rear passenger but invisible from a second side of the transparent screen to a driver so the driver can look through the transparent screen and out of a rear windshield of the automobile, the method comprising: 
 locating the transparent screen in a line of sight of the driver to the rear windshield of the automobile; and    projecting the image (1) through a first polarizer and (2) onto a second polarizer on the transparent screen, wherein the first polarizer has a first polarization direction and the second polarizer has a second polarization direction different from the first polarization direction.    
   
   
       7 . (canceled)  
   
   
       8 . The method of  claim 6 , wherein the projector and the first polarizer are located on the first side of the transparent screen.  
   
   
       9 . The method of  claim 6 , wherein said projecting the image onto a second polarizer comprises reflecting the image onto the second polarizer on the transparent screen.  
   
   
       10 . The method of  claim 6 , wherein the first polarizer is located on a lens of a projector.  
   
   
       11 - 20 . (canceled)  
   
   
       21 . An automobile, comprising: 
 a display system, comprising a transparent screen having an image that is visible from a first side of the transparent screen to a rear passenger and invisible from a second side of the transparent screen to a driver so the driver can look through the transparent screen and out of a rear windshield of the automobile.    
   
   
       22 . A method for providing display in an automobile, comprising: 
 providing an image on a first side of a transparent screen in the automobile;    preventing the image from appearing on a second side of the transparent screen, wherein the image is visible from the first side of the transparent screen to a rear passenger but invisible from the second side of the transparent screen to a driver so the driver can look through the transparent screen and out of a rear windshield of the automobile.