Polarizing plate for minimizing reflective properties in organic light emitting device
Provided are a polarizing plate and a display. The illustrative polarizing plate may exhibit desired characteristics in a wide range of wavelengths, and have excellent reflection and visibility at an inclined angle. For example, the polarizing plate may be used in a reflective or transflective liquid crystal display or an organic light emitting device.
1. A polarizing plate for minimizing reflection in an organic light emitting device, comprising:
a polarizer; and a retardation layer laminated on one side of the polarizer,
wherein a reflectivity measure on a side of the polarizer of the polarizing plate is 12% or less at an inclined angle of 50 degrees and the inclined angle is an angle between a normal line of a surface of the polarizing plate and an observation direction,
wherein the retardation layer comprises a uniaxial retardation film or a biaxial retardation film,
wherein an angle between a slow axis of the uniaxial retardation film or the biaxial retardation film and a light absorption axis of the polarizer is from 40 degrees to 50 degrees,
wherein a thickness direction retardation (Rth) of the retardation layer according to the equation Rth=d×(Nz−Ny) is from 5 nm to 300 nm,
wherein d is a thickness of the retardation layer, and Ny and Nz are refractive indexes in y and z axes of the retardation layer, respectively, wherein the y axis is a direction parallel to a fast axis of the retardation layer and z axis is a normal direction of a plane formed by the x and y axes, wherein the x axis is a direction parallel to a slow axis of the retardation layer,
wherein the retardation layer satisfies R(450)/R(550)<R(650)/R(550),
wherein R(450) is an in-plane retardation of the uniaxial retardation film or the biaxial retardation film with respect to light having a wavelength of 450 nm, R(550) is an in-plane retardation of the uniaxial retardation film or the biaxial retardation film with respect to light having a wavelength of 550 nm, and R(650) is an in-plane retardation of the uniaxial retardation film or the biaxial retardation film with respect to light having a wavelength of 650 nm, wherein R(450)/R(550) is in a range from 0.81 to 0.99, and R(650)/R(550) is in a range from 1.01 to 1.19.
2. The polarizing plate according to claim 1 , wherein the uniaxial retardation film is a positive uniaxial retardation film and wherein the retardation layer further comprises a C plate.
3. The polarizing plate according to claim 1 , wherein the biaxial retardation film is a positive biaxial retardation film.
4. The polarizing plate according to claim 1 , wherein the uniaxial retardation film is a positive uniaxial retardation film and wherein the retardation layer further comprises a positive biaxial retardation film.
5. The polarizing plate according to claim 1 , wherein the biaxial retardation film is a negative biaxial retardation film and wherein the retardation layer further comprises a positive biaxial retardation film.
6. The polarizing plate according to claim 1 , wherein the biaxial retardation film is a positive biaxial retardation film and wherein the retardation layer further comprises a negative biaxial retardation film.
7. The polarizing plate according to claim 1 , wherein the biaxial retardation film is a negative biaxial retardation film and wherein the retardation layer further comprises a C plate.
8. An organic light emitting device comprising the polarizing plate of claim 1 and an electrode layer,
wherein the electrode layer is transparent or reflective and wherein the polarizing plate is disposed on the outer surface of the electrode layer, to which external light reaches first.