| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cellulose acylate film decreased in a change of optical anisotropy according to an environmental change and capable of giving a picture display device having no deterioration of a picture display performance even in case of occurrence of the environmental change. <P>SOLUTION: This cellulose acylate film is formed by casting a cellulose acylate composition containing a cellulose acylate, a wavelength dispersion controlling agent, a polymerizable compound, and a polymerization initiator, and then irradiating the cast composition with light, wherein the cellulose acylate film has a ratio of a value of Re<SB>λ</SB>[Re<SB>λ</SB>is a front retardation value (unit: nm) of the film at a wavelength of λ (nm) and defined by equation: Re<SB>λ</SB>=(n<SB>x</SB>-n<SB>y</SB>)×d (n<SB>x</SB>is an in-plane refractive index in the direction of a delayed phase axis; n<SB>y</SB>is an in-plane refractive index in the direction of an advanced phase axis; and d is a thickness of the film)] measured at 10 %RH to a value thereof measured at 80 %RH of ≥0.65, and further has has a ratio of a value of Rth<SB>λ</SB>[Rth<SB>λ</SB>is a retardation value (unit: nm) in the direction of the thickness of the film at a wavelength of λ (nm) and defined by equation: Rth<SB>λ</SB>=ä(n<SB>x</SB>+n<SB>y</SB>)/2-n<SB>z</SB>}×d (n<SB>z</SB>is a refractive index in the direction of the thickness)] measured at 10 %RH to a value thereof measured at 80 %RH of ≥0.65. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
