Image display device having polarizer with polarizer protection
Provided is an image display device including an image display cell and a polarizing plate placed on a viewer side of the image display cell. The first polarizing plate includes a polarizer and a first protective film. The first protective film is placed on a viewer-side principal surface of the polarizer and satisfies following relations: (i) 0 nm≦Re 1 ≦3000 nm; (ii) Nz 1 ≧7; and (iii) Rth 1 >2500 nm. Re 1 , Rth 1 and Nz 1 are defined by following equations: Re 1 =(nx 1 −ny 1 )d 1 ; Rth 1 =(nx 1 −nz 1 )d 1 ; and Nz 1 =Rth 1 /Re 1 , wherein d 1 represents a thickness of the first protective film, nx 1 represents a refractive index in a direction of an in-plane slow axis of the protective film, ny 1 represents a refractive index in a direction of an in-plane fast axis of the protective film, and nz 1 represents a refractive index in a direction of the thickness of the protective film.
1. An image display device, comprising:
an image display cell; and
a first polarizing plate placed on a viewer side of the image display cell,
wherein the first polarizing plate comprises a polarizer and a first protective film,
wherein the first protective film is placed on a viewer-side principal surface of the polarizer and satisfies following relations:
350 nm≦Re 1 ≦3000 nm; (i)
Nz 1 ≧7; and (ii)
Rth 1 >2500 nm, (iii)
wherein Re 1 , Rth 1 and Nz 1 are defined by following equations:
Re 1 =( nx 1 −ny 1 ) d 1 ;
Rth 1 =( nx 1 −nz 1 ) d 1 ; and
Nz 1 =Rth 1 /Re 1 ,
wherein d 1 represents a thickness of the first protective film, nx 1 represents a refractive index in a direction of an in-plane slow axis of the protective film, ny 1 represents a refractive index in a direction of an in-plane fast axis of the protective film, and nz 1 represents a refractive index in a direction of the thickness of the protective film.
2. The image display device according to claim 1 , wherein the first protective film comprises aromatic polyester as a main component.
3. The image display device according to claim 2 , wherein the aromatic polyester is polyethylene terephthalate or polyethylene naphthalate.