Optical filter for anti-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, a first retardation film having an Nz value of 1 to 1.5 according to Equation 1, and a second retardation film having an Nz value of −1 or less in Equation 1, wherein in-plane slow axes of the first retardation film and the second retardation film each form 43 degrees to 47 degrees with the absorption axis of said polarizer:
Nz =( nx−nz )/( nx−ny ) Equation 1:
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 the Nz value of the first retardation film is 1, and the in-plane slow axes of the first retardation film and the second retardation film are orthogonal to each other.
3. The optical filter according to claim 1 , wherein the Nz value of the first retardation film is more than 1 and 1.5 or less, and the in-plane retardation axes of the first retardation film and the second retardation film are orthogonal to each other.
4. The optical filter according to claim 1 , wherein the Nz value of the first retardation film is 1, and the in-plane slow axes of the first retardation film and the second retardation film are parallel to each other.
5. The optical filter according to claim 1 , wherein the Nz value of the first retardation film is more than 1 and 1.5 or less, and the in-plane retardation axes of the first retardation film and the second retardation film are parallel to each other.
6. The optical filter according to claim 1 , wherein the lower limit of the Nz value of the second retardation film is −11,000 or more.
7. The optical filter according to claim 1 , wherein the first retardation film has an in-plane retardation of 70 nm to 200 nm for light having a wavelength of 550 nm.
8. The optical filter according to claim 1 , wherein the in-plane slow axes of the first retardation film and the second retardation film are orthogonal to each other, and said first retardation film has an in-plane retardation of 120 nm to 200 nm.
9. The optical filter according to claim 1 , wherein the in-plane slow axes of the first retardation film and the second retardation film are parallel to each other, and said first retardation film has an in-plane retardation of 70 nm to 160 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 an in-plane retardation of more than 0 nm and 70 nm or less for light having a wavelength of 550 nm.
12. The optical filter according to claim 1 , wherein said second retardation film has a thickness-direction retardation calculated by Equation 7 of 50 nm to 200 nm:
R th= d ×{( nz −( nx+ny )/2} Equation 7:
wherein, nx, ny and nz are the same as defined in claim 1 , and d means a thickness of the retardation film.
13. An organic light-emitting device comprising the optical filter of claim 1 and an organic light-emitting display panel.
14. The organic light-emitting device according to claim 13 , wherein the first retardation film of the optical filter is disposed adjacent to the organic light-emitting display panel as compared with the polarizer.