Circularly polarizing plate

Abstract

Provided is a circularly polarizing plate that is excellent in antireflection characteristic, and that can be produced at low cost. The circularly polarizing plate of the present invention includes in the stated order: a polarizer; a retardation layer (20a) configured to function as a λ/4 plate; and a colored layer, wherein an angle formed by an absorption axis of the polarizer and a slow axis of the retardation layer (20a) is from 35° to 55°, wherein the colored layer has an absorption peak in a wavelength band in a range of from 580 nm to 610 nm, and wherein the colored layer contains a compound X represented by the general formula (I) or the general formula (II).

1 . A circularly polarizing plate, comprising in the stated order:
 a polarizer;   a retardation layer “a” configured to function as a λ/4 plate; and   a colored layer,   wherein an angle formed by an absorption axis of the polarizer and a slow axis of the retardation layer “a” is from 35° to 55°,   wherein the colored layer has an absorption peak in a wavelength band in a range of from 580 nm to 610 nm, and   wherein the colored layer contains a compound X represented by the following general formula (I) or general formula (II):   
       
         
           
           
               
               
           
         
       
       in the formula (I),
 R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8  each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms, a substituent represented by the formula (a), or a substituent represented by the formula (b), 
 R 1  and R 2  form a saturated cyclic skeleton including 5 or 6 carbon atoms, and R 3 , R 4 , R 5 , R 6 , R 7 , and R 8  each independently represent a hydrogen atom, a halogen atom, which is preferably Cl, a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms, a substituent represented by the formula (a), or a substituent represented by the formula (b), 
 R 2  and R 3  form a saturated cyclic skeleton including 5 to 7 carbon atoms, and R 1 , R 4 , R 5 , R 6 , R 7 , and R 8  each independently represent a hydrogen atom, a halogen atom, which is preferably Cl, a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms, a substituent represented by the formula (a), or a substituent represented by the formula (b), 
 R 5  and R 6  form a saturated cyclic skeleton including 5 or 6 carbon atoms, and R 1 , R 2 , R 3 , R 4 , R 7 , and R 8  each independently represent a hydrogen atom, a halogen atom, which is preferably Cl, a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms, a substituent represented by the formula (a), or a substituent represented by the formula (b), 
 R 6  and R 7  form a saturated cyclic skeleton including 5 to 7 carbon atoms, and R 1 , R 2 , R 3 , R 4 , R 5 , and R 8  each independently represent a hydrogen atom, a halogen atom, which is preferably Cl, a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms, a substituent represented by the formula (a), or a substituent represented by the formula (b), 
 R 1  and R 2  form a saturated cyclic skeleton including 5 or 6 carbon atoms, R 5  and R 7  form a saturated cyclic skeleton including 5 or 6 carbon atoms, and R 3 , R 4 , R 7 , and R 8  each independently represent a hydrogen atom, a halogen atom, which is preferably Cl, a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms, a substituent represented by the formula (a), or a substituent represented by the formula (b), or 
 R 2  and R 3  form a saturated cyclic skeleton including 5 to 7 carbon atoms, R 5  and R 7  form a saturated cyclic skeleton including 5 to 7 carbon atoms, and R 1 , R 4 , R 5 , and R 8  each independently represent a hydrogen atom, a halogen atom, which is preferably Cl, a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms, a substituent represented by the formula (a), or a substituent represented by the formula (b); and 
 in the formula (II), R 4  and R 8  each independently represent a hydrogen atom, or a substituted or unsubstituted alkyl group having 1 or more and 20 or less carbon atoms. 
 
     
     
         2 . The circularly polarizing plate according to  claim 1 , wherein a laminate including the polarizer and the colored layer has a polarization degree of 99.9% or more. 
     
     
         3 . The circularly polarizing plate according to  claim 1 , further comprising a retardation layer “b” configured to function as a λ/2 plate between the polarizer and the retardation layer “a” configured to function as a λ/4 plate,
 wherein the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer “a” is from 65° to 85°, and 
 wherein an angle formed by the absorption axis of the polarizer and a slow axis of the retardation layer “b” is from 10° to 20°. 
 
     
     
         4 . The circularly polarizing plate according to  claim 1 , wherein the colored layer further has an absorption peak in a wavelength band in a range of from 440 nm to 510 nm. 
     
     
         5 . The circularly polarizing plate according to  claim 1 ,
 wherein the retardation layer “a” configured to function as a λ/4 plate has a ratio Re(450)/Re(550) of 0.5 or more and less than 1.0, and   wherein the retardation layer “a” has an Nz coefficient of from 0.3 to 0.7.   
     
     
         6 . An image display apparatus, comprising the circularly polarizing plate of  claim 1 . 
     
     
         7 . The image display apparatus according to  claim 6 , further comprising an image display panel, wherein the image display panel has a visible light reflectance of 20% or more.