Optical film and display device
An optical film includes a transparent substrate having opposite first and second surfaces, a colored layer formed to face the first surface of the substrate, and an optical function layer. A colorant in the colored layer contains at least one of a first coloring material having a maximum absorption wavelength in a range of 470 to 530 nm and an absorption spectral half width of 15 to 45 nm, a second coloring material having a maximum absorption wavelength in a range of 560 to 620 nm and an absorption spectral half width of 15 to 55 nm, and a third coloring material having the lowest transmittance in a wavelength range of 400 to 800 nm is in a range of 650 to 800 nm. A transmittance in one of the absorption wavelength bands of the colorant is 1% or more and less than 50%, and ΔE*ab.
1 . An optical film, comprising:
a sheet-like transparent substrate having a first surface and a second surface opposite the first surface;
a colored layer that is formed to face the first surface of the transparent substrate and contains a colorant; and
an optical function layer formed on the colored layer, wherein
the colorant contains at least one of
a first coloring material having a maximum absorption wavelength in a range of 470 to 530 nm and an absorption spectral half width of 15 to 45 nm,
a second coloring material having a maximum absorption wavelength in a range of 560 to 620 nm and an absorption spectral half width of 15 to 55 nm, and
a third coloring material in which a wavelength having the lowest transmittance in a wavelength range of 400 to 800 nm is in a range of 650 to 800 nm,
in one of absorption wavelength bands of the colorant, a transmittance is 1% or more and less than 50%,
the optical function layer includes a layer that has an ultraviolet shielding rate according to JIS L 1925 of 85% or more and a pencil hardness at a surface load of 500 g of H or above, and
ΔE*ab, which is a chromaticity difference between before and after a light resistance test of irradiating for 120 hours with a xenon lamp having an illuminance at wavelengths of 300 to 400 nm of 60 W/cm 2 under the conditions of a temperature of 45° C. and a humidity of 50% RH, satisfies Equation (1) below:
ΔE*ab≤5 Equation (1), wherein the second coloring material is a metal complex of a compound having a tetraazaporphyrin structure.
2 . The optical film of claim 1 , wherein the colored layer contains at least one of a radical scavenger, a peroxide decomposer, and a singlet oxygen quencher.
3 . The optical film of claim 2 , wherein the radical scavenger is a hindered amine photostabilizer having a molecular weight of 2,000 or more.
4 . The optical film of claim 2 , wherein the singlet oxygen quencher is a transition metal complex of dialkyl phosphate, dialkyl dithiocarbamate, or benzene dithiol or similar dithiol.
5 . The optical film of any claim 1 , wherein the optical function layer includes an oxygen barrier layer having oxygen barrier properties in which an oxygen permeability is 10 cc/(m 2 ·day·atm) or less.
6 . The optical film of claim 1 , wherein
the optical function layer includes an ultraviolet shielding layer constituted by a cured film of a composition that contains an energy radiation-curing compound, a photoinitiator, and an ultraviolet absorber,
an absorption wavelength region in an ultraviolet region of the photoinitiator is different from an absorption wavelength region in an ultraviolet region of the ultraviolet absorber, and
the absorption wavelength region in the ultraviolet region of the ultraviolet absorber is in a range of 290 to 370 nm.
7 . The optical film of claim 1 , wherein
the optical function layer includes an ultraviolet shielding layer constituted by a cured film of a composition that contains an energy radiation-curing compound, a photoinitiator, and an ultraviolet absorber, and
the optical function layer includes, sequentially from a side facing the colored layer, the ultraviolet shielding layer and a low refractive index layer having a refractive index lower than that of the ultraviolet shielding layer.
8 . The optical film of claim 1 , wherein
the optical function layer includes an ultraviolet shielding layer constituted by a cured film of a composition that contains an energy radiation-curing compound, a photoinitiator, and an ultraviolet absorber, and
the optical function layer includes, sequentially from a side facing the colored layer, the ultraviolet shielding layer and an anti-glare layer.
9 . The optical film of claim 1 , wherein
the optical function layer includes an ultraviolet shielding layer constituted by a cured film of a composition that contains an energy radiation-curing compound, a photoinitiator, and an ultraviolet absorber, and
the ultraviolet shielding layer is an anti-glare layer that contains an ultraviolet absorber.
10 . The optical film of claim 1 , wherein
the optical function layer includes an ultraviolet shielding layer constituted by a cured film of a composition that contains an energy radiation-curing compound, a photoinitiator, and an ultraviolet absorber,
the optical function layer includes, sequentially from a side facing the colored layer, the ultraviolet shielding layer and a low refractive index layer having a refractive index lower than that of the ultraviolet shielding layer, and
the ultraviolet shielding layer is an anti-glare layer that contains an ultraviolet absorber.
11 . The optical film of claim 1 , wherein each of the first coloring material and the third coloring material is a compound having a structure selected from the group consisting of porphyrin structure, merocyanine structure, phthalocyanine structure, azo structure, cyanine structure, squarylium structure, coumarin structure, polyene structure, quinone structure, tetraazaporphyrin structure, pyrromethene structure, and indigo structure, or a metal complex thereof.
12 . A display device, comprising:
a light source; and
the optical film of claim 1 disposed in such a manner that the second surface of the transparent substrate faces the light source.
13 . The optical film of claim 1 , wherein the second coloring material is a tetraazaporphyrin copper complex dye.