Polarization mirror hmd with increased brightness

Abstract

An optical system and, specifically an HMD, is disclosed for increasing brightness efficiency of light transmitted from a display. By including one polarization selective mirror between a half mirror and a display and another polarization selective mirror between the half mirror and a lens, brightness efficiency is increased without a substantial increase in thickness.

What is claimed is: 
     
         1 . The optical system comprising:
 an optical arrangement providing at least two light paths for the emitted light, wherein the optical arrangement comprises:   a first polarization selective mirror configured to transmit a first polarization component of the emitted light;   a second polarization selective mirror configured to transmit a second polarization component of the emitted light; and   a partial mirror between the first polarization selective mirror and the second polarization selective mirror, wherein the first polarization selective mirror and the second polarization selective mirror are such that the at least two light paths are substantially collinear when exiting the optical arrangement.   
     
     
         2 . The optical system of  claim 1 , further comprising a lens, wherein the lens is between the first polarization selective mirror and the second polarization selective mirror . 
     
     
         3 . The optical system of  claim 1 , further comprising a lens, wherein at least one of the first polarization selective mirror, the second polarization selective mirror, and the partial mirror is either integrated in the lens or adhered to a surface of the lens. 
     
     
         4 . The optical system of  claim 1 , further comprising:
 a first retarder film between the first polarization selective mirror and the partial mirror; and   a second retarder film between the partial mirror and the second polarization selective mirror.   
     
     
         5 . The optical system of  claim 4 , wherein:
 the partial mirror is a half mirror;   the first retarder film is a first quarter wave plate; and   the second retarder film is a second quarter wave plate.   
     
     
         6 . The optical system of  claim 4 , wherein the first retarder film and the second retarder film are arranged symmetrically with respect to the partial mirror. 
     
     
         7 . The optical system of  claim 1 , wherein the first polarization selective mirror and the second polarization selective mirror are arranged symmetrically with respect to the partial mirror. 
     
     
         8 . The optical system of  claim 1 , wherein the first polarization component is orthogonal to the second polarization component. 
     
     
         9 . The optical system of  claim 1 , wherein the at least two light paths are substantially collinear when exiting the optical arrangement. 
     
     
         10 . The optical system of  claim 1 , wherein the emitted light is linearly polarized having the first polarization component. 
     
     
         11 . The optical system of  claim 1 , further comprising a refracting medium that supports the optical arrangement such that different wavelengths of the emitted light are not laterally separated. 
     
     
         12 . The optical system comprising:
 an optical arrangement providing at least two light paths for the emitted light, wherein the optical arrangement comprises:   a first linear polarization selective mirror configured to transmit a first polarization component of the light;   a second linear polarization selective mirror configured to transmit a second polarization component of the light;   a half mirror between the first linear polarization selective mirror and the second linear polarization selective mirror;   a first quarter wave plate between the first linear polarization selective mirror and the half mirror; and   a second quarter wave plate between the half mirror and the second linear polarization selective mirror, wherein the first linear polarization selective mirror and the second linear polarization selective mirror are such that the at least two light paths are substantially collinear when exiting the optical arrangement.   
     
     
         13 . The optical system of  claim 12 , further comprising a lens, wherein the optical arrangement is between the first polarization selective mirror and the second polarization selective mirror. 
     
     
         14 . The optical system of  claim 13 , further comprising a plural of lenses, wherein the plural of lenses is between the first polarization selective mirror and the second polarization selective mirror. 
     
     
         15 . The optical system of  claim 12 , further comprising a lens, wherein at least one of the first linear polarization selective mirror, the second linear polarization selective mirror, the half mirror, the first quarter wave plate, and the second quarter wave plate is either integrated in the lens or adhered to a surface of the lens. 
     
     
         16 . The optical system of  claim 15 , further comprising a lens, wherein the first linear polarization selective mirror and the first quarter wave plate, is either integrated in the lens or adhered to a surface of the lens 
     
     
         17 . The optical system of  claim 12 , wherein:
 the first linear polarization selective mirror and the second linear polarization selective mirror are arranged symmetrically with respect to the half mirror; and   the first quarter wave plate and the second quarter wave plate are arranged symmetrically with respect to the half mirror.   
     
     
         18 . The optical system of  claim 12 , wherein the at least two light paths are substantially collinear when exiting the optical arrangement. 
     
     
         19 . The optical system of  claim 12 , wherein:
 the emitted light is linearly polarized having the first polarization component; and   the first polarization component is orthogonal to the second polarization component.   
     
     
         20 . The optical system of  claim 12 , further comprising a refracting medium that supports the optical arrangement such that different wavelengths of the emitted light are not laterally separated.