Optical illumination apparatus

Abstract

An optical illumination apparatus has a polarization conversion device for converting light from a light source into light polarized uniformly in a predetermined manner and an optical integrator system for illuminating a display panel with the light polarized in the predetermined manner. The polarization conversion device splits the light from the light source into a first light beam and a second light beam in such a way that the first and second light beams are polarized in different manners, and then converts one of the first and second light beams into light polarized in the identical manner as the other light beam. Moreover, the first and second light beams pass through an identical lens cell of a first lens array of the optical integrator system and are imaged on an identical lens cell of a second lens array of the optical integrator system.

1 . (Once Amended) An optical illumination apparatus comprising: 
 a polarization conversion device for converting light from a light source into light uniformly polarized in a predetermined manner; and    an optical integrator system for illuminating a display panel with the light polarized in the predetermined manner, the optical integrator system comprising a first lens array having an array of first lens cells, and a second lens array having an array of second lens cells;    wherein the polarization conversion device is adapted to split the light from the light source into a first light beam and a second light beam such that the first and second light beams are polarized in different manners, and to convert one of the first and second light beams into light polarized in an identical manner as the other of the first and second light beams; and    wherein a portion of the thus converted one of the first and second light beams and a portion of the other of the first and second light beams pass through one cell of the first lens array and are imaged on a corresponding cell of the second lens array.    
     
     
         2 . An optical illumination apparatus in accordance with  claim 1 , wherein the light from the light source is split into the first and second light beams in a direction corresponding to longer sides of the display panel.  
     
     
         3 . An optical illumination apparatus in accordance with  claim 1 , wherein an optical relationship between the first and second light beams is represented by a formula:  
       0.3< l· tan  9 θ/ d< 0.75  
       wherein: 
 θ represents an angle between the first and second light beams;  
 l represents an optical distance between the first and second lens arrays; and  
 d represents a size of each lens cell, along longer sides of the second lens array.  
 
     
     
         4 . An optical illumination apparatus in accordance with  claim 1 , further comprising a color switching device disposed between the polarization conversion device and the optical integrator system, the color switching device adapted to time-divisionally switch colors of the light polarized in the predetermined manner from one color to another among a plurality of predetermined colors.  
     
     
         5 . An optical illumination apparatus in accordance with  claim 4 , wherein the color switching device is a cholesteric liquid crystal device.  
     
     
         6 . An optical illumination apparatus in accordance with  claim 4 , wherein the color switching device is a hologram formed of a liquid crystal polymer.  
     
     
         7 . An optical illumination apparatus in accordance with  claim 4 , wherein the color switching device comprises: 
 a diffraction grating, and    a reflective light valve.    
     
     
         8 . An optical illumination apparatus in accordance with  claim 1 , wherein the first lens array comprises a plurality of lens cells, the first and second light beams form a first group, the polarization conversion device being adapted to further split the light from the light source into a second group such that the first and second groups travel in horizontally symmetric directions with respect to a direction in which an image is displayed, and individual lens cells of the first lens array are decentered in horizontally symmetric directions with respect to the direction in which the image is displayed.  
     
     
         9 . An optical illumination apparatus in accordance with  claim 1 , wherein the polarization conversion device comprises a plurality of polarizing beam splitter prisms arranged in parallel.  
     
     
         10 . An optical illumination apparatus in accordance with  claim 1 , wherein the polarization conversion device comprises: 
 a first polarizing beam splitter prism; and    a second polarizing beam splitter prism;    wherein the first polarizing beam splitter prism is adapted to transmit light polarized in a first manner and to reflect light polarized in a second manner to the second polarizing beam splitter prism; and    wherein the second polarizing beam splitter prism is adapted to reflect the light polarized in the second manner received from the first polarizing beam splitter prism.    
     
     
         11 . An optical illumination apparatus in accordance with  claim 1 , wherein the first lens array comprises a plurality of the first lens cells arranged in a rectangular grid array.  
     
     
         12 . An optical illumination apparatus in accordance with  claim 11 , wherein the rectangular grid array has an aspect ratio that is substantially identical to an aspect ratio of the display panel.  
     
     
         13 . An optical illumination apparatus in accordance with  claim 1 , wherein the second lens array comprises a plurality of the second lens cells arranged in a rectangular grid array.  
     
     
         14 . An optical illumination apparatus, comprising: 
 a polarization conversion device for splitting light from a light source into first and second light beams polarized in first and second manners and for converting one of first and second light beams into light polarized in an identical manner as the other of the first and second light beams;    a cholesteric liquid crystal device for switching colors of the first and second light beams on a time-divisional basis; and    an optical integrator system for illuminating a display panel with the first and second light beams, the optical integrator system comprising a first lens array having a first lens cell, and a second lens array having a second lens cell;    wherein the first and second light beams pass through the first lens cell and are imaged on the second lens cell.    
     
     
         15 . An optical illumination apparatus in accordance with  claim 14 , wherein the cholesteric liquid crystal device comprises: 
 a layer of cholesteric liquid crystal elements; and    a controller for bringing the layer into a first state wherein light of a particular wavelength is reflected, and into a second state wherein all light is transmitted through the layer.    
     
     
         16 . An optical illumination apparatus in accordance with  claim 14 , wherein the polarization conversion device comprises: 
 a first polarizing beam splitter prism adapted to transmit P-polarized light and to reflect S-polarized light;    a first quarter-wave plate disposed behind the first polarizing beam splitter prism, adapted to receive the P-polarized light therefrom and to convert the P-polarized light to right-handed circularly polarized light;    a second polarizing beam splitter prism disposed parallel to the first polarizing beam splitter prism, adapted to receive the S-polarized light therefrom and to reflect the S-polarized light; and    a second quarter-wave plate disposed behind the second polarizing beam splitter prism, adapted to receive the S-polarized light therefrom and to convert the S-polarized light to right-handed circularly polarized light.    
     
     
         17 . An optical illumination apparatus in accordance with  claim 16 , further comprising a quarter wave plate for converting circularly polarized light into linearly polarized light, the quarter wave plate being disposed between the cholesteric liquid crystal device and the optical integrator system.  
     
     
         18 . An optical illumination apparatus, comprising: 
 a polarization conversion device for splitting light from a light source into first and second light beams polarized in different manners and for converting one of first and second light beams into light polarized in an identical manner as the other of the first and second light beams;    a liquid crystal hologram device for switching colors of the first and second light beams on a time-divisional basis; and    an optical integrator system for illuminating a display panel with the first and second light beams, the optical integrator system comprising a first lens array having a first lens cell, and a second lens array having a second lens cell;    wherein the first and second light beams pass through the first lens cell and are imaged on the second lens cell.    
     
     
         19 . An optical illumination apparatus in accordance with  claim 18 , wherein the polarization conversion device comprises: 
 a first polarizing beam splitter prism adapted to transmit S-polarized light and to reflect P-polarized light;    a second polarizing beam splitter prism, adapted to reflect the P-polarized light received from the first polarizing beam splitter prism; and    a half-wave plate disposed behind the second polarizing beam splitter prism, adapted to convert the P-polarized light therefrom to S-polarized light.    
     
     
         20 . An optical illumination apparatus in accordance with  claim 18 , wherein the liquid crystal hologram device comprises: 
 a layer of liquid crystal hologram elements; and    a controller for bringing the layer into a first state wherein light of a particular wavelength is reflected and diffracted, and into a transparent state wherein all light is transmitted through the layer;    wherein the light that is reflected and diffracted exits from the liquid crystal hologram device in a direction oblique to its surface.    
     
     
         21 . An optical illumination apparatus, comprising: 
 a polarization conversion device for splitting light from a light source into first and second light beams polarized in different manners and for converting one of first and second light beams into light polarized in an identical manner as the other of the first and second light beams;    a diffraction grating for separating colors of the first and second light beams;    a reflective light valve for switching the colors of the first and second light beams on a time-divisional basis; and    an optical integrator system for illuminating a display panel with the first and second light beams, the optical integrator system comprising a first lens array having a first lens cell, and a second lens array having a second lens cell;    wherein the first and second light beams pass through the first lens cell and are imaged on the second lens cell.    
     
     
         22 . An optical illumination apparatus in accordance with  claim 21 , wherein the polarization conversion device comprises: 
 a first polarization separation mirror adapted to transmit light polarized in a first manner and to reflect light polarized in a second manner;    a second polarization separation mirror disposed proximate the first polarization separation mirror, adapted to reflect the light polarized in the second manner received from the first polarization separation mirror; and    a half-wave plate disposed behind the second polarization separation mirror, adapted to receive the light polarized in the second manner therefrom and to convert the light polarized in the second manner to light polarized in the first manner.    
     
     
         23 . An optical illumination apparatus in accordance with  claim 21 , further comprising a fresnal lens disposed between the polarization conversion device and the diffraction grating.  
     
     
         24 . An optical illumination apparatus in accordance with  claim 21 , further comprising a controller for separately driving each of red, green, and blue regions of the reflective light valve.