Polarizing plate and liquid crystal display including the same

1. A polarizing plate, comprising:

a polarizer; and

a stretched polyester film on a first side of the polarizer, the polyester film having a stretched direction corresponding to a transverse direction (TD) of the film, the polyester film having a ratio of machine direction (MD) elongation (Elongation MD ) to transverse direction (TD) elongation (Elongation TD ) of about 1:6 to about 1:30, wherein the MD elongation is calculated by Equation 4MD and the TD elongation is calculated by Equation 4TD:

Elongation MD (%)={( L 1MD −L 0MD )/ L 0MD }×100,  Equation 4MD

wherein, in Equation 4MD, L 0MD denotes an initial MD length, and L 1MD denotes a final MD length after stretching of the polyester film using a universal test machine at a rate of 100 mm/min;

Elongation TD (%)={( L 1TD −L 0TD )/ L 0TD }×100,  Equation 4TD

wherein, in Equation 4TD, L 0TD denotes an initial TD length, and L 1TD denotes a final TD length after stretching of the polyester film using a universal test machine at a rate of 100 mm/min,

wherein an angle between a transmission axis of the polarizer and the TD of the polyester film ranges from about −7° to about +7°, and wherein the polarizing plate has a degree of polarization of 99.99% or greater.

2. The polarizing plate according to claim 1 , wherein the polyester film has a crystallinity of about 50% to about 100%.

3. The polarizing plate according to claim 1 , wherein the polyester film has an in-plane retardation (Re) at a wavelength of 550 nm of about 5,000 nm to about 15,000 nm, as calculated by Equation 1, and an out-of-plane retardation (Rth) at a wavelength of 550 nm of about 6,000 nm to about 18,000 nm, as calculated by Equation 2:

Equation 1

Re =( nx−ny )× d   (1)

Equation 2

Rth =[{( nx+ny )/2}− nz]×d   (2)

wherein:

nx, ny, and nz are indices of refraction in the MD, the TD, and a thickness direction of the polyester film, respectively, the MD defining an x-axis, the TD defining a y-axis, and the thickness direction defining a z-axis;

the x-axis, the y-axis, and the z-axis are orthogonal to one another; and

d is a thickness of the film in nm.

4. The polarizing plate according to claim 1 , wherein the polyester film has a degree of biaxiality (NZ) at a wavelength of 550 nm of about 1.0 to about 1.8, as calculated by Equation 3:

NZ =( nx−nz )/( nx−ny )  (3)

wherein:

nx, ny, and nz are indices of refraction in the MD, the TD, and a thickness direction of the polyester film, respectively, the MD defining an x-axis, the TD defining a y-axis, and the thickness direction defining a z-axis; and

the x-axis, the y-axis, and the z-axis are orthogonal to one another.

5. The polarizing plate according to claim 1 , wherein the polyester film comprises at least one of a polyethylene terephthalate (PET) resin, a polybutylene terephthalate resin, a polyethylene naphthalate resin, and a polybutylene naphthalate resin.

6. The polarizing plate according to claim 1 , further comprising:

an adhesive layer comprising a solvent-free adhesive between the polarizer and the polyester film.

7. The polarizing plate according to claim 6 , wherein the solvent-free adhesive comprises about 90 wt % to about 95 wt % of a (meth)acrylic adhesive resin and about 5 wt % to about 10 wt % of an isocyanate curing agent.

8. The polarizing plate according to claim 1 , further comprising:

an optical film on a second side of the polarizer.

9. A liquid crystal display comprising the polarizing plate according to claim 1 .