Liquid crystal film
A liquid crystal film (LCF) is provided. The exemplified LCF can be used as a reflective polarization plate, which can improve luminance and light utilization efficiency of a display device, such as an LCD, and the like.
1. A liquid crystal display device comprising an optical device, a liquid crystal panel, and a light source arranged on one side of the liquid crystal panel,
wherein the optical deviceis arranged between the liquid crystal panel and the light source,
wherein the optical device satisfies the following Formula 4 or Formula 5, and the optical device comprises:
a liquid crystal film comprising a substrate and a liquid crystal layer formed on at least one side of the substrate,
wherein the side of the substrate on which the liquid crystal layer is formed has a wetting angle of 30° to 50°,
wherein the liquid crystal layer is a single layer and comprises at least two types of cholesteric-aligned liquid crystal areas, of which center wavelengths of reflected light are different from each other, and has a haze value of 15% to 30%,
wherein the at least two types of cholesteric-aligned liquid crystal areas comprise a first liquid crystal area on which a helical axis of a director of a cholesteric liquid crystal molecule is formed parallel to a thickness direction of the liquid crystal layer, and a second liquid crystal area on which the helical axis of the director of the cholesteric liquid crystal molecules formed is formed not parallel to a thickness direction of the liquid crystal layer,
and a λ/4 wavelength layer formed on one side or both sides of the liquid crystal film:
| X 1− X 2|≦0.1 [Formula 4]
| Y 1− Y 2|≦0.1 [Formula 5]
where, X 2 and Y 2 are an x value and a y value in a tristimulus value of CIE color space of light penetrated through the by irradiating to one side of the optical device, respectively; and
X 1 and Y 1 are an x value and a y value in the tristimulus value of the CIE color space before light irradiated to the optical device penetrates through the optical device.
2. The liquid crystal display device of claim 1 , wherein the liquid crystal area comprises a first area of which a center wavelength of reflected light of 400 nm to 500 nm, a second area of which a center wavelength of reflected light of 500 nm to 600 nm, and a third area of which a center wavelength of reflected light of 600 nm to 700 nm.
3. The liquid crystal display device of claim 1 , wherein the liquid crystal layer comprises a compound represented by the following Chemical Formula 1 in a polymerized form:
where, A is a single bond, —COO—, or —OCO—; and
R 1 to R 10 are independently hydrogen, a halogen, an alkyl group, an alkoxy group, cyano group, a nitro group, —O-Q-P, or a substituent of the following Chemical Formula 2, respectively, with the proviso that at least one of R 1 to R 10 is —O-Q-P or a substituent of the following Chemical Formula 2, where Q is an alkylene group or an alkylidene group, and P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group
where, B is a single bond, —COO—, or —OCO—; and
R 11 to R 15 are independently hydrogen, a halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group, or —O-Q-P, respectively, with the proviso that at least one of R 11 to R 15 is —O-Q-P, where Q is an alkylene group or an alkylidene group, and P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.
4. The liquid crystal display device of claim 1 , wherein the liquid crystal film further comprises a resin layer that is formed on one side or both sides of the liquid crystal layer and that comprises a particle.
5. The liquid crystal display device of claim 4 , wherein the particle has a different refractive index from the resin layer.
6. The liquid crystal display device of claim 1 , wherein the substrate is an optically isotropic substrate, an optically anisotropic substrate, or a polarization element.
7. The liquid crystal display device of claim 6 , wherein the optically anisotropic substrate is a λ/4 wavelength layer or a λ/2 wavelength layer.
8. The liquid crystal display device of claim 1 , wherein the liquid crystal film is manufactured by a method of manufacturing a liquid crystal film, comprising: forming a liquid crystal layer that is a single layer and that comprises at least two types of cholesteric-aligned liquid crystal areas, of which center wavelengths of reflected light are different from each other; and controlling a haze value of 15% to 30% by forming the liquid crystal layer on the side of the substrate having a wetting angle of 0° to 50° so that the liquid crystal area comprises a first liquid crystal area on which a helical axis of a director of a cholesteric liquid crystal molecule is formed parallel to a thickness direction of the liquid crystal layer, and a second liquid crystal area on which the helical axis of the director of the cholesteric liquid crystal molecule is not parallel to a thickness direction of the liquid crystal layer.
9. The liquid crystal display device of claim 8 , wherein the liquid crystal layer is formed by irradiating a coating layer of a cholesteric liquid crystal composition comprising a liquid crystal compound of the following Chemical Formula 1, a chiral agent, and a photoinitiator with ultraviolet ray having a wavelength of ultraviolet ray A at an intensity of 10 to 500 mJ/cm 2 under the temperature from 40° C. to 80° C., and then irradiating the coating layer with ultraviolet ray having a wavelength of ultraviolet ray A to C at an intensity of 1 mJ/cm 2 to 10 mJ/cm 2 :
where, A is a single bond, —COO—, or —OCO—; and
R 1 to R 10 are independently hydrogen, a halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group, —O-Q-P, or a substituent of the following Chemical Formula 2, respectively, with the proviso that at least one of R 1 to R 10 is —O-Q-P or a substituent of the following Chemical Formula 2, where Q is an alkylene group or an alkylidene group, and P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group
where, B is a single bond, —COO—, or —OCO—; and
R 11 to R 15 are independently hydrogen, a halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group, or —O-Q-P, respectively, with the proviso that at least one of R 11 to R 15 is —O-Q-P, where Q is an alkylene group or an alkylidene group, and P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.
10. The liquid crystal display device of claim 8 , wherein the method of manufacturing a liquid crystal film further comprises forming a resin layer on one side or both sides of the liquid crystal layer, the resin layer being formed by curing a coating layer that comprises a curable composition that is at least one selected from the group consisting of a room temperature curable composition, a moisture curable composition, a heat curable composition, an active energy ray curable composition, or a hybrid curable composition; and a particle.
11. The liquid crystal display device of claim 1 , further comprising a polarization element arranged on the upper side of the λ/4 wavelength layer.
12. The liquid crystal display device of claim 1 , wherein the is arranged so that the liquid crystal film is located closer to the light source than the λ/4 wavelength layer.