POLARIZING PLATE AND OPTICAL DISPLAY APPARATUS
A polarizing plate and an optical display apparatus are provided. The polarizing plate includes a polarizer; and a retardation layer including a laminate of a positive C layer and a negative B layer and stacked on one surface of the polarizer, wherein the negative B layer has a degree of biaxiality of 1.5 or more at a wavelength of 550 nm, and the negative B layer has a Raman spectrum value of 10.20 or more as defined by Equation 1 in the disclosure.
1 . A polarizing plate comprising:
a polarizer; and
a retardation layer on a surface of the polarizer and comprising a positive C layer and a negative B layer,
wherein the negative B layer has a degree of biaxiality of 1.5 or more at a wavelength of 550 nm and a Raman spectrum value of 10.20 or more, as defined according to Equation 1:
Raman
spectrum
value
=
A
/
B
,
(
1
)
where A is a value calculated by Equation 1-1:
A
=
❘
"\[LeftBracketingBar]"
(
@
921
cm
-
1
/
MD
)
/
❘
"\[RightBracketingBar]"
(
@
1445
cm
-
1
/
MD
)
,
(
1
-
1
)
in Equation 1-1, I(@921 cm −1 /MD) being intensity of a resulting Raman spectrum at a wavenumber of 921 cm −1 in a machine direction (MD) of the negative B layer, and
I(@1445 cm −1 /MD) being intensity of a resulting Raman spectrum at a wavenumber of 1,445 cm −1 in the MD of the negative B layer; and
where B is a value calculated by Equation 1-2:
B
=
❘
"\[LeftBracketingBar]"
(
@
921
cm
-
1
/
TD
)
/
❘
"\[RightBracketingBar]"
(
@
1445
cm
-
1
/
TD
)
,
(
1
-
2
)
in Equation 2-1, I(@921 cm −1 /TD) being intensity of a resulting Raman spectrum at a wavenumber of 921 cm −1 in a transverse direction (TD) of the negative B layer, and
I(@1445 cm −1 /TD) being intensity of a resulting Raman spectrum at a wavenumber of 1,445 cm −1 in the TD of the negative B layer.
2 . A polarizing plate comprising:
a polarizer; and
a retardation layer on a surface of the polarizer and comprising a positive C layer and a negative B layer,
wherein the negative B layer has a degree of biaxiality of 1.5 or more at a wavelength of 550 nm and an FT-IR spectrum value of 1.20 or more, as defined according to Equation 2:
FT
-
IR
spectrum
value
=
C
/
D
(
2
)
where C is a value calculated by Equation 2-1:
C
=
❘
"\[LeftBracketingBar]"
(
@
2860
cm
-
1
/
MD
)
/
❘
"\[RightBracketingBar]"
(
@
1445
cm
-
1
/
MD
)
(
2
-
1
)
in Equation 2-1, I(@2860 cm −1 /MD) being intensity of a resulting FT-IR spectrum at a wavenumber of 2,860 cm −1 in a machine direction (MD) of the negative B layer, and
I(@1445 cm −1 /MD) being intensity of a resulting FT-IR spectrum at a wavenumber of 1,445 cm −1 in the MD of the negative B layer; and
where D is a value calculated by Equation 2-2:
D
=
❘
"\[LeftBracketingBar]"
(
@
2860
cm
-
1
/
TD
)
/
❘
"\[RightBracketingBar]"
(
@
1445
cm
-
1
/
TD
)
(
2
-
2
)
in Equation 2-2, I(@2860 cm −1 /TD) being intensity of a resulting FT-IR spectrum at a wavenumber of 2,860 cm −1 in a transverse direction (TD) of the negative B layer, and
I(@1445 cm −1 /TD) being intensity of a resulting FT-IR spectrum at a wavenumber of 1,445 cm −1 in the TD of the negative B layer.
3 . The polarizing plate as claimed in claim 1 , wherein the negative B layer is between the polarizer and the positive C layer.
4 . The polarizing plate as claimed in claim 1 , wherein the negative B layer comprises a resin having positive birefringence.
5 . The polarizing plate as claimed in claim 1 , wherein the negative B layer comprises a cyclic olefin polymer resin.
6 . The polarizing plate as claimed in claim 1 , wherein the negative B layer is a TD uniaxially stretched film.
7 . The polarizing plate as claimed in claim 1 , wherein the negative B layer has an in-plane retardation of about 70 nm to about 150 nm at a wavelength of 550 nm.
8 . The polarizing plate as claimed in claim 1 , wherein the negative B layer has an out-of-plane retardation of about 35 nm to about 195 nm at a wavelength of 550 nm.
9 . The polarizing plate as claimed in claim 1 , wherein the positive C layer has an out-of-plane retardation of about −150 nm to about −70 nm at a wavelength of 550 nm.
10 . The polarizing plate as claimed in claim 1 , wherein the positive C layer is a coating layer comprising at least one of a cellulosic compound or a polymer thereof, or an aromatic compound or a polymer thereof.
11 . The polarizing plate as claimed in claim 1 , wherein the retardation layer is on a light incidence surface or a light exit surface of the polarizer.
12 . The polarizing plate as claimed in claim 1 , wherein a thickness of a laminate of the positive C layer and the negative B layer is about 95% or more of a thickness of the retardation layer.
13 . The polarizing plate as claimed in claim 1 , further comprising: a protective layer on a surface of the polarizer.
14 . The polarizing plate as claimed in claim 1 , wherein the polarizing plate further comprises a first protective layer, the first protective layer being on a surface of the polarizer and between the polarizer and the positive C layer.
15 . The first protective layer of claim 14 , wherein the first protective layer has a front in-plane retardation and an out-of-plane retardation of each about 10 nm or less at a wavelength of 550 nm.
16 . The polarizing plate as claimed in claim 2 , wherein the negative B layer is between the polarizer and the positive C layer.
17 . The polarizing plate as claimed in claim 2 , wherein the negative B layer comprises a resin having positive birefringence.
18 . The polarizing plate as claimed in claim 2 , wherein the negative B layer comprises a cyclic olefin polymer resin.
19 . An optical display apparatus comprising the polarizing plate as claimed in claim 1 .
20 . An optical display apparatus comprising the polarizing plate as claimed in claim 2 .