Multilayer film, optically anisotropic laminate, circular polarizer, organic electroluminescent display, and manufacturing methods

Abstract

A multilayer film including: a first long-length substrate; and an optically anisotropic layer that is formed directly on the first substrate and contains cured liquid-crystal molecules, wherein the first substrate has an orientation-controlling force caused by stretching, and a slow axis of the first substrate is different from a lengthwise direction of the first substrate; an optically anisotropic laminate, a circular polarizing plate, and an organic EL display device having the anisotropic layer; as well as manufacturing method thereof.

1 . A multilayer film comprising:
 a first long-length substrate; and   an optically anisotropic layer that is formed directly on the first substrate and contains cured liquid-crystal molecules, wherein   the first substrate has an orientation-controlling force caused by stretching, and   a slow axis of the first substrate is different from a lengthwise direction of the first substrate.   
     
     
         2 . The multilayer film according to  claim 1 , wherein the slow axis of the first substrate and the lengthwise direction of the first substrate form an angle of 10° to 90°. 
     
     
         3 . The multilayer film according to  claim 2 , wherein the slow axis of the first substrate and the lengthwise direction of the first substrate form an angle of 40° to 50°. 
     
     
         4 . The multilayer film according to  claim 1 , wherein the first substrate is a film of a resin having a positive intrinsic birefringence. 
     
     
         5 . The multilayer film according to any  claim 1 , wherein the first substrate is a film of a resin containing an alicyclic structure-containing polymer or a film of cellulose ester. 
     
     
         6 . The multilayer film according to  claim 1 , wherein the first substrate is a stretched film obtained by widthwise stretching or diagonal stretching. 
     
     
         7 . The multilayer film according to  claim 1 , wherein the optically anisotropic layer has inverse wavelength distribution. 
     
     
         8 . The multilayer film according to  claim 1 , wherein the optically anisotropic layer is a λ/4 wave plate. 
     
     
         9 . The multilayer film according to  claim 1 , wherein the optically anisotropic layer is a λ/2 wave plate. 
     
     
         10 . The multilayer film according to  claim 1 , wherein the optically anisotropic layer has a thickness of 5 μm or less. 
     
     
         11 . The multilayer film according to  claim 1 , wherein the cured liquid-crystal molecules of the optically anisotropic layer have homogeneous orientation regularity in substantially a same direction as a direction of the slow axis of the first substrate. 
     
     
         12 . The multilayer film according to  claim 1 , wherein the optically anisotropic layer formed on the first substrate is obtained by applying onto the first substrate a liquid crystal composition containing a polymerizable liquid crystal compound to form a layer of the liquid crystal composition, giving homogeneous orientation to the polymerizable liquid crystal composition in the layer, the orientation being in substantially a same direction as a direction of the slow axis of the first substrate, and
 polymerizing the polymerizable liquid crystal compound to form the cured liquid-crystal molecules.   
     
     
         13 . The multilayer film according to  claim 1 , wherein the first substrate has a birefringence Δn of 0.000050 or more. 
     
     
         14 . An optically anisotropic laminate obtained by separating the optically anisotropic layer from the multilayer film according to  claim 1  and
 attaching the optically anisotropic layer to a second long-length substrate. 
 
     
     
         15 . A circular polarizing plate obtained by attaching an optically anisotropic layer to a long-length linear polarizer by a roll-to-roll process, wherein the optically anisotropic layer is a layer separated from the multilayer film according to  claim 1 . 
     
     
         16 . An organic electroluminescent display device comprising the circular polarizing plate according to  claim 15 . 
     
     
         17 . A method for manufacturing the multilayer film according to  claim 1 , comprising:
 a step (I) of feeding out a long-length first substrate in the lengthwise direction, the first substrate having an orientation-controlling force caused by stretching, wherein a slow axis of the first substrate is different from a lengthwise direction of the first substrate;   a step (II) of directly applying onto a surface of the fed-out first substrate a liquid crystal composition containing a polymerizable liquid crystal compound to form a layer of the liquid crystal composition;   a step (III) of giving orientation to the polymerizable liquid crystal compound in the layer of the liquid crystal composition; and   a step (IV) of polymerizing the polymerizable liquid crystal compound to form cured liquid-crystal molecules.   
     
     
         18 . The method for manufacturing the multilayer film according to  claim 17 , wherein an applying direction of the liquid crystal composition is different from an orientation direction of the polymerizable liquid crystal compound.