Circularly polarizing plate
A circularly polarizing plate capable of improving the tone of reflective color sense by using a retardation film having flat dispersion characteristics; and an OLED device comprising the circularly polarizing plate.
1. A circularly polarizing plate comprising sequentially:
an antireflection film;
a polarizer;
a retardation film having an R(450)/R(550) value of 0.99 to 1.01 where R (λ) is an in-plane retardation value for a wavelength of λ nm; and
a pressure-sensitive adhesive layer,
wherein the antireflection film has a lowest reflection wavelength of 470 nm or less, the retardation film has an in-plane retardation value of 136.0 nm or more for a wavelength of 550 nm, and the circularly polarizing plate has a transmittance of 30% or less for a wavelength of 430 nm,
wherein in the antireflection film, reflection colors satisfy a L*a*b* color coordinate criteria of a*>0, b*>0 and a*<b*.
2. The circularly polarizing plate according to claim 1 , wherein the lowest reflection wavelength of the antireflection film is 390 nm or more.
3. The circularly polarizing plate according to claim 1 , wherein the antireflection film has a haze of 1% or less.
4. The circularly polarizing plate according to claim 1 , wherein the polarizer has a transmittance for a wavelength of 550 nm in a range of 40% to 50%.
5. The circularly polarizing plate according to claim 1 , wherein the in-plane retardation value of the retardation film for a wavelength of 550 nm is 143 nm or less.
6. The circularly polarizing plate according to claim 1 , wherein a slow axis of the retardation film forms an angle of 43 degrees to 47 degrees with an absorption axis of the polarizer.
7. The circularly polarizing plate according to claim 1 , wherein the retardation film is a liquid crystal polymerization film or a polymer stretched film.
8. The circularly polarizing plate according to claim 1 , wherein the circularly polarizing plate has a transmittance of 40% or more for wavelengths of 460 nm and 550 nm.
9. The circularly polarizing plate according to claim 1 , wherein the circularly polarizing plate has a transmittance of 4% or more for a wavelength of 430 nm.
10. The circularly polarizing plate according to claim 1 , wherein the circularly polarizing plate further comprises a dye exhibiting a maximum absorbance for a wavelength in a range of 370 nm to 430 nm.
11. An OLED (organic light emitting diode) device comprising an OLED panel and the circularly polarizing plate of claim 1 disposed on one side of the OLED panel.
12. The OLED device according to claim 11 , wherein the OLED panel has an average reflectance of 45% or less for a wavelength in a range of 410 nm to 500 nm and an average reflectance of 50% or less for a wavelength in a range of 600 nm to 650 nm.
13. The OLED device according to claim 11 , wherein the OLED panel, to which the circularly polarizing plate is attached, has a reflectance of 1.3% or less for a wavelength of 550 nm.
14. The OLED device according to claim 11 , wherein reflection colors of the OLED panel, to which the circularly polarizing plate is attached, satisfy a L*a*b* color coordinate criteria of a*<8 and b*>−8.5.