Optical filter for preventing reflection and organic light-emitting device
The present application relates to an optical filter and an organic light-emitting display device. The optical filter of the present application has excellent omnidirectional antireflection performance and color characteristics on the side as well as the front, and the optical filter can be applied to an organic light-emitting device to improve visibility.
1. An optical filter for anti-reflection comprising:
a polarizer having an absorption axis formed in one direction, an optical compensation layer, a first retardation film having an Nz value of 0.8 to 1.2 according to Equation 1, and having an in-plane slow axis forming 43 degrees to 47 degrees with the absorption axis of said polarizer, wherein said optical compensation layer comprises a third retardation film having an Nz value of −4.0 or less according to Equation 1 or satisfying Equation 2;
a second retardation film having an Nz value of −4.0 or less in Equation 1;
wherein each of the second retardation film and the third retardation film is a C plate and has a thickness-direction retardation value of 0 nm to 200 nm; satisfying Equation 2, in sequence:
Nz =( nx−nz )/( nx−ny ) Equation 1:
nx=ny<nz Equation 2:
wherein, nx, ny, and nz are refractive indexes in the x-axis, y-axis and z-axis directions of the retardation film, the x-axis is a direction parallel to the in-plane slow axis of the retardation film, the y-axis is a direction parallel to an in-plane fast axis of the retardation film, and the z-axis is a thickness direction of the retardation film.
2. The optical filter according to claim 1 , wherein said optical compensation layer further comprises a fourth retardation film having an Nz value of 0.8 to 1.2 according to Equation 1 and having an in-plane slow axis parallel or orthogonal to the absorption axis of said polarizer.
3. The optical filter according to claim 2 , wherein said third retardation film is closer to the polarizer than said fourth retardation film, and the in-plane slow axis of said fourth retardation film is parallel to the absorption axis of said polarizer.
4. The optical filter according to claim 2 , wherein said fourth retardation film is closer to the polarizer than said third retardation film, and the in-plane slow axis of said fourth retardation film is orthogonal to the absorption axis of said polarizer.
5. The optical filter according to claim 2 , wherein said fourth retardation film is closer to the polarizer than said third retardation film, and the in-plane slow axis of said fourth retardation film is parallel to the absorption axis of said polarizer.
6. The optical filter according to claim 2 , wherein said third retardation film is closer to the polarizer than said fourth retardation film, and the in-plane slow axis of said fourth retardation film is orthogonal to the absorption axis of said polarizer.
7. The optical filter according to claim 1 , wherein the second retardation film and the third retardation film have each an R (450)/R (550) value of 0.7 to 1.3, and R (λ) means a thickness-direction retardation of the retardation film for light of λ nm.
8. The optical filter according to claim 2 , wherein said fourth retardation film has an R (450)/R (550) value of 0.7 to 1.3, and R (λ) means an in-plane retardation of the retardation film for light of λ nm.
9. The optical filter according to claim 1 , wherein said first retardation film has an in-plane retardation of 130 nm to 150 nm for light having a wavelength of 550 nm.
10. The optical filter according to claim 1 , wherein said first retardation film has an R (450)/R (550) of 0.60 to 0.92, and R (λ) means an in-plane retardation of the retardation film for light of λ nm.
11. The optical filter according to claim 1 , wherein said second retardation film has the Nz value in Equation 1 of −4.0 or less.
12. The optical filter according to claim 1 , wherein said third retardation film has the Nz value in Equation 1 of −4.0 or less.
13. The optical filter according to claim 2 , wherein said fourth retardation film has an in-plane retardation of 0 nm to 180 nm for light having a wavelength of 550 nm.
14. An organic light-emitting device comprising the optical filter of claim 1 and an organic light-emitting display panel.
15. The organic light-emitting device according to claim 14 , wherein the first retardation film of the optical filter is disposed adjacent to the organic light-emitting display panel as compared with the polarizer.