Single-path color video projection systems employing corrective optics

Abstract

A multimedia projector ( 100 ) includes a single-path frame-sequential color optical system in which light rays emitted by a light source ( 14 ) propagate through a color wheel ( 102 ) and an optical integrator ( 16, 120, 122 ), and are directed toward a transflective polarizing beam splitter ( 40 ) that separates them into P-polarized components ( 76 ) and S-polarized components ( 78 ). The P-polarized components are transmitted toward a reflective LCD ( 26 ) in which pixels in a dark state reflect the light rays without a polarization change and return them through the transflective polarizing beam splitter, whereas pixels in a bright state reflect the light rays with a 90° polarization change as S-polarized light rays ( 112 ), which are reflected by the transflective polarizing beam splitter toward a projection lens ( 27 ).

1 - 18 . (cancelled)  
     
     
         19 . An apparatus, comprising: 
 a light source adapted to emit light;    an aspherical corrector lens adapted to receive the light and to transmit the light to an aspherical collimating lens that is adapted to substantially collimate the light; and    a light homogenizing device adapted to receive the light from the aspherical collimating lens and to substantially homogenize the light.    
     
     
         20 . The apparatus of  claim 19 , wherein the light source is further adapted to emit polychromatic light and the apparatus further comprises: 
 a color modulation device through which the aspherical corrector lens is adapted to focus the polychromatic light, said color modulation device being adapted to transmit frame sequential color (“FSC”) light to the aspherical collimating lens.    
     
     
         21 . The apparatus of  claim 20 , wherein the color modulation device comprises a selected one of a color wheel or a liquid crystal-based color switching device.  
     
     
         22 . The apparatus of  claim 19 , wherein the light source comprises: 
 an aspherical reflector with a first focal point; and    an arc lamp adapted to emit light at the first focal point.    
     
     
         23 . The apparatus of  claim 19 , wherein the light homogenizing device comprises a selected one of a flyseye lens array or an optical integrator.  
     
     
         24 . A system comprising: 
 a light source adapted to emit light;    an aspherical corrector lens adapted to receive the light and to transmit the light to an aspherical collimating lens that is adapted to substantially collimate the light;    a light homogenizing device adapted to receive the light from the aspherical collimating lens and to substantially homogenize the light;    a plate-type transflective polarizing beam splitter adapted to receive the light from the light homogenizing device, to transmit rays of the light polarized in a first polarization direction, and to reflect rays of the light polarized in a second polarization direction; and    a reflective light valve adapted to receive the light polarized in the first polarization direction, the reflective light valve including pixels selectively switchable between first and second states such that pixels switched to the first state reflect the light in the first polarization direction back through the transflective polarizing beam splitter, and pixels switched to the second state reflect the light in the second polarization direction for reflection off the transflective polarizing beam splitter as image bearing light.    
     
     
         25 . The system of  claim 24 , wherein the reflective light valve has an aspect ratio, and in which the light transmitted through the light homogenizing flyseye lens array further has a cross-sectional aspect ratio that substantially matches the aspect ratio of the reflective light valve.  
     
     
         26 . The system of  claim 24 , further comprising: 
 a projection lens adapted to project the image bearing light.    
     
     
         27 . The system of  claim 26 , further comprising: 
 a light polarizing filter, disposed between the transflective polarizing beam splitter and the projection lens, adapted to correct for non-ideal light transmission and reflection responses of the transflective polarizing beam splitter.    
     
     
         28 . The system of  claim 24 , in which the plate-type transflective polarizing beam splitter includes at least one of a group consisting of a wire grid device, a multi-layer thin film device, a cholesteric polymer liquid crystal device, and a laminated polymer sheet device.  
     
     
         29 . The system of  claim 24 , wherein the light source is further adapted to emit polychromatic light and the system further comprises: 
 a color modulation device through which the aspherical lens is adapted to focus the polychromatic light, said color modulation device being adapted to transmit frame sequential color (“FSC”) light to the aspherical collimating lens.    
     
     
         30 . The system of  claim 29 , wherein the color modulation device includes a color wheel or a liquid crystal-based color switching device.