Compensator with photochemically cured barrier layer and process

Abstract

Disclosed is an optical compensator for a liquid crystal display comprising a transparent polymeric support, a photochemically cured barrier layer impermeable to the components of the support, an orientation layer, and a photochemically cured optically anisotropic layer, in order, wherein the photochemically cured barrier layer as disposed on the support has an indentation modulus of less than 2 GPa.

What is claimed is:  
     
         1 . An optical compensator for a liquid crystal display comprising a transparent polymeric support, a photochemically cured barrier layer impermeable to the components of the support, an orientation layer, and a photochemically cured optically anisotropic layer, in order, wherein the photochemically cured barrier layer as disposed on the support has an indentation modulus of less than 2 GPa.  
     
     
         2 . The compensator of  claim 1  wherein the dry thickness of the barrier layer is from 0.10-10 g/m 2 .  
     
     
         3  The compensator of  claim 1  wherein the dry thickness of the barrier layer is from 0.55-5 g/m 2 .  
     
     
         4 . The compensator of  claim 1  wherein said transparent support comprises a cellulose ester.  
     
     
         5 . The compensator of  claim 1  wherein said transparent support comprises a polycarbonate.  
     
     
         6 . The compensator of  claim 1  wherein said optically anisotropic layer comprises a nematic liquid crystal.  
     
     
         7 . The compensator of  claim 1  wherein the orientation layer conatins a meterial that is capable of orientation by rubbing.  
     
     
         8 . The compensator of  claim 1  wherein the orientation layer contains materials that are capable of orientation through photoalignment using polarized light.  
     
     
         9 . The compensator of  claim 1  wherein the orientation layer layer comprises a polyvinyl cinnamate.  
     
     
         10 . The compensator of  claim 1  wherein the anisotropic layer contains a nematic liquid crystal material.  
     
     
         11 . The compensator of  claim 1  wherein the optic axis of the anisotropic layer has a fixed azimuthal angle.  
     
     
         12 . The compensator of  claim 1  wherein the optic axis of the anisotropic layer has a fixed tilt angle.  
     
     
         13 . The compensator of  claim 1  wherein the optic axis of the anisotropic layers has a variable tilt angle.  
     
     
         14 . The compensator of  claim 11  wherein the optic axis of the anisotropic layer has a variable tilt angle.  
     
     
         15 . The compensator of  claim 1  wherein the optic axis of the anisotropic layer has a variable tilt angle and a variable azimuthal angle.  
     
     
         16 . The compensator of  claim 1  wherein the anisotropic layers contain a material with positive birefringence.  
     
     
         17 . The compensator of  claim 1  wherein the transparent polymer support is triacetyl cellulose.  
     
     
         18 . The compensator of  claim 1  further comprising a compliant layer between the support and the barrier layer.  
     
     
         19 . The compensator of  claim 18  wherein the compliant layer has an indentation modulus of less than 2 GPa.  
     
     
         20 . The compensator of  claim 18  wherein the dry thickness of the compliant layer is from 0.10-10 g/m 2 .  
     
     
         21  The compensator of  claim 18  wherein the dry thickness of the compliant layer is from 0.55-5 g/m 2 .  
     
     
         22 . A liquid crystal display (LCD) comprising the compensator of  claim 1 .  
     
     
         23 . A liquid crystal display (LCD) comprising the compensator of  claim 18 .  
     
     
         24 . An electronic imaging device comprising an LCD of  claim 22 .  
     
     
         25 . An electronic imaging device comprising an LCD of  claim 23 .  
     
     
         26 . A method of forming a component of  claim 1  comprising aligining the orientation layer using a photo-alignment step.  
     
     
         27 . A process for forming an optical compensator of  claim 1  comprising: 
 a) coating and drying the layers in order on the support,  
 b) at least partly photochemically curing the barrier layer after the original coating;  
 c) coating an orientation layer comprising a photo-alignable polymer in a solvent over the barrier layer;  
 d) drying the orientation layer;  
 e) photo-aligning the orientation layer in a predetermined direction;  
 f) coating an anisotropic nematic liquid crystal layer comprising a polymerizable material in a solvent carrier over the orientation layer;  
 g) drying the anisotropic layer;  
 h) photochemically curing the anisotropic layer; and  
 i) repeating the above steps c) through h) coating over the anisotropic layer obtained from h) but photo-aligning the orientation layer at a predetermined angle to the direction in step e); 
 provided that the photochemical curing steps, in toto, are sufficient so that the final photochemically cured barrier layer as disposed on the support has an indentation modulus of less than 2 GPa.  
 
 
     
     
         28 . The process of  claim 27  wherein the predetermined angle of step i) to the angle in step e) is 90°.  
     
     
         29 . The process of  claim 27  wherein the photochemically curable polymer in the barrier layer is coated from a dipersion or solution containing water, an alcohol, a hydrocarbon, an alkyl halide, ester, ketone, or ether.  
     
     
         30 . The process of  claim 27  wherein the photo-exposure conditions used to cure the optically anisotropic layer are UV light of wavelength from 280 to 420 nm.  
     
     
         31 . The process of  claim 27  wherein the photo-exposure conditions used to cure the optically anisotropic layer are UV light of wavelength from 320 to 410 nm.