Reflective liquid crystal light valve

Abstract

Reflective liquid crystal light valves are disclosed. A liquid crystal cell is also disclosed comprising a transparent electrode, a reflective electrode, and a twisted nematic liquid crystal layer interposed therebetween. A first alignment layer with a first alignment direction disposed on the transparent electrode. A second alignment layer with a second alignment direction disposed on the reflective electrode, wherein a first included angle φ is between the first and second alignment directions. A polarizing device is disposed on the exterior of the transparent electrode to provide an incident beam having a polarization direction, wherein a second included angle β is between the first alignment direction and the polarization direction. A relationship between the first included angle φ and the second included angle β satisfies φ/2<β<φ/2+30° or 90°+φ/2<β<φ/2+120°.

1 . A reflective light valve, comprising: 
 a transparent substrate disposed opposite a reflective substrate with a twisted nematic type liquid crystal material interposed therebetween;    a first alignment layer with a first alignment direction disposed on the transparent substrate;    a second alignment layer with a second alignment direction disposed on the reflective substrate, wherein a first included angle φ is between the first and second alignment directions; and    a polarizing device disposed on an exterior of the transparent substrate to provide an incident beam having a polarization direction, wherein a second included angle β is between the first alignment direction and the polarization direction;    wherein a relationship between the first included angle φ and the second included angle β satisfies φ/2<β<φ/2+30° or 90°+φ/2<β<φ/2+120°.    
   
   
       2 . The reflective light valve according to  claim 1 , wherein the second included angle β is φ/2+1° to about 3°.  
   
   
       3 . The reflective light valve according to  claim 2 , wherein the second included angle β is φ/2+1.5°.  
   
   
       4 . The reflective light valve according to  claim 1 , wherein the first included angle φ is between 40° and 70°.  
   
   
       5 . The reflective light valve according to  claim 1 , wherein the transparent substrate is a glass substrate comprising a transparent electrode formed thereon.  
   
   
       6 . The reflective light valve according to  claim 5 , wherein the transparent electrode is an indium tin oxide (ITO) or indium zinc oxide (IZO) layer.  
   
   
       7 . The reflective light valve according to  claim 1 , wherein the reflective substrate is a silicon substrate comprising a metal electrode formed thereon.  
   
   
       8 . The reflective light valve according to  claim 7 , wherein the metal electrode is an aluminum layer.  
   
   
       9 . The reflective light valve according to  claim 1 , wherein the twisted nematic type liquid crystal material comprises positive dielectric anisotropic liquid crystal molecules.  
   
   
       10 . A reflective light valve, comprising: 
 a liquid crystal cell comprising a transparent electrode, a reflective electrode and a twisted nematic liquid crystal layer interposed therebetween, wherein a retardation value (dΔn) of the twisted nematic liquid crystal layer is about 350 nm;    a first alignment layer with a first alignment direction disposed on the transparent electrode;    a second alignment layer with a second alignment direction disposed on the reflective electrode, wherein a first included angle φ is between the first and second alignment directions; and    a polarizing device disposed on an exterior of the transparent electrode to provide an incident beam having a polarization direction, wherein a second included angle β is between the first alignment direction and the polarization direction;    wherein a relationship between the first included angle φ and the second included angle β satisfies φ/2<β<φ/2+30° or 90°+φ/2<β<φ/2+120°.    
   
   
       11 . The reflective light valve according to  claim 10 , wherein the second included angle β is φ/2+1° to about 3°.  
   
   
       12 . The reflective light valve according to  claim 11 , wherein the second included angle β is φ/2+1.5°.  
   
   
       13 . The reflective light valve according to  claim 10 , wherein the first included angle φ is between 40° and 70°.  
   
   
       14 . The reflective light valve according to  claim 10 , wherein the transparent electrode is an ITO or IZO layer and the reflective electrode is an aluminum layer.  
   
   
       15 . The reflective light valve according to  claim 10 , wherein the twisted nematic type liquid crystal layer comprises positive dielectric anisotropic liquid crystal molecules.  
   
   
       16 . A reflective light valve, comprising: 
 a liquid crystal cell comprising a transparent electrode on a transparent substrate, a reflective electrode on a semiconductor substrate and a twisted nematic liquid crystal layer interposed therebetween;    a first alignment layer with a first alignment direction disposed on the transparent electrode;    a second alignment layer with a second alignment direction disposed on the reflective electrode, wherein a first included angle φis between the first and second alignment directions; and    a polarizing beam splitter disposed on an exterior of the transparent substrate to provide an incident beam having a polarization direction, wherein a second included angle β is between the first alignment direction and the polarization direction;    wherein a relationship between the first included angle φ and the second included angle β satisfies φ/2<β<φ/2+1°˜3° or 90°+φ/2<β<φ/2+91°˜93°.    
   
   
       17 . The reflective light valve according to  claim 16 , wherein the second included angle β is φ/2+1.5°.  
   
   
       18 . The reflective light valve according to  claim 16 , wherein the first included angle φ is between 40° and 70°.  
   
   
       19 . The reflective light valve according to  claim 16 , wherein the twisted nematic type liquid crystal layer comprises positive dielectric anisotropic liquid crystal molecules.  
   
   
       20 . An electronic device, comprising: 
 a reflective light valve of  claim 16;     a controller coupled to the reflective light valve; and    an input device coupled to the controller to input data to the controller to render an image.