Optical laminate
An optical laminate is provided. When the optical laminate is applied to an OLED display device, the problem of visibility due to reflection of external incident natural light of the device can be solved, and simultaneously its display quality can also be improved.
1. An optical laminate which is not a polarizing plate, comprising:
a pressure-sensitive adhesive layer including a pressure-sensitive adhesive resin and light scattering particles having a refractive index different from that of the pressure-sensitive adhesive resin, wherein a haze of the pressure-sensitive adhesive layer as measured according to the standard of JIS K7105 is 40% or more;
a transmittance control layer having a transmittance of 10% to 80% for light with a wavelength in a range of 380 nm to 780 nm; and
an antireflection layer having a reflectance of 2% or less for light with a wavelength in a range of 380 nm to 780 nm,
wherein the transmittance control layer is laminated on the pressure-sensitive adhesive layer, and the antireflection layer is laminated on the transmittance control layer, and
wherein the transmittance control layer comprises a binder resin, a green light absorbing dye, a yellow light absorbing dye, a red light absorbing dye and a blue light absorbing dye.
2. The optical laminate according to claim 1 , wherein the pressure-sensitive adhesive resin has a refractive index greater than that of the light scattering particles.
3. The optical laminate according to claim 1 , wherein the light scattering particles are acrylic resin particles, styrene resin particles, styrene-acrylic copolymer particles, polyethylene particles, urethane resin particles, melamine resin particles, benzoguanamine resin particles, epoxy resin particles, silicone resin particles, silica particles, titanium oxide particles, magnesium fluoride particles, zirconium oxide particles, aluminum oxide particles or glass particles.
4. The optical laminate according to claim 1 , wherein the light scattering particles have an average particle diameter (D50) in a range of 1 μm to 20 μm.
5. The optical laminate according to claim 1 , wherein the pressure-sensitive adhesive layer comprises the light scattering particles in a ratio ranging from 1 part by weight to 30 parts by weight relative to 100 parts by weight of the pressure-sensitive adhesive resin.
6. The optical laminate according to claim 1 , wherein the pressure-sensitive adhesive layer is located on an opposite side of the antireflection layer based on the transmittance control layer.
7. The optical laminate according to claim 1 , wherein the antireflection layer comprises a hard coating layer and a lowly refractive coating layer having a refractive index lower than that of the hard coating layer.
8. The optical laminate according to claim 7 , wherein the lowly refractive coating layer comprises a first region having a refractive index of 1.55 or more for light with a wavelength in a range of 400 nm to 700 nm and a second region having a refractive index of 1.45 or less for light with a wavelength in a range of 400 nm to 700 nm, and the second region is located on an opposite side of the hard coating layer based on the first region.
9. The optical laminate according to claim 8 , wherein when ellipticity of polarization measured by ellipsometry for each of the first region and the second region in the lowly refractive coating layer has been optimized using a Cauchy model of following equation 1,
n
(
λ
)
=
A
+
B
λ
2
+
C
λ
4
[
Equation
1
]
wherein n(λ) is a refractive index at a wavelength of λ, λ is in a range of 300 nm to 1800 nm, and A, B and C are each a Cauchy parameter;
wherein the first region and the second region in the lowly refractive coating layer satisfy at least one of the following conditions 1 to 3:
[Condition 1]
wherein a difference between an A value for the first region and an A value for the second region is 0.2 or more;
[Condition 2]
wherein, the A value for the first region is in a range of 1.50 to 2.00; and
[Condition 3]
wherein the A value for the second region is in a range of 1.00 to 1.40.
10. A display device comprising an organic light emitting panel and the optical laminate of claim 1 , wherein the optical laminate is attached to the organic light emitting panel via the pressure-sensitive adhesive layer.
11. The display device according to claim 10 , comprising no retardation plate.
12. The display device according to claim 10 , wherein the optical laminate is attached to a side of the organic light emitting panel, from which light is emitted, via the pressure-sensitive adhesive layer.
13. The display device according to claim 12 , wherein the optical laminate is directly attached to the side of the organic light emitting panel, from which light is emitted, via the pressure-sensitive adhesive layer.
14. The display device according to claim 10 , wherein an a* value of a reflective color coordinate system in a range of −2 to 2, and an b* value of the reflective color coordinate system is in a range of −2 to 2.
15. The optical laminate according to claim 1 , wherein the haze of the pressure-sensitive adhesive layer as measured according to the standard of JIS K7105 is 40% or more.
16. The optical laminate according to claim 1 , wherein the reflectance of the antireflection layer is 0.01% or more for light with a wavelength in a range of 380 nm to 780 nm.
17. The optical laminate according to claim 8 , wherein the refractive index of the first region is 1.95 or less for light with the wavelength in a range of 400 nm to 700 nm.