Optical film
Provided are an optical film and a display device including the same. The optical film may be disposed at the outermost side of a display device, such as a liquid crystal display or an organic light emitting display, or at an outside of a polarizing layer of the display in which the polarizing layer is disposed at a visible side. The film disposed as described above may overcome degradation of brightness that may occur when an observer watches an image with polarizing sunglasses. The optical film may also have hardness suitable for its use.
1. An optical film, which is disposed at the outermost side of a display device or at an outside of a polarizing layer of the display device in which the polarizing layer is disposed at a visible side, comprising:
a liquid crystal layer having an in-plane retardation with respect to light with a wavelength of 550 nm of 80 nm to 200 nm, and a surface hardness of 3H or more,
wherein the liquid crystal layer is a cured layer of a liquid crystal composition comprising a polymerizable liquid crystal material, the polymerizable liquid crystal material comprising:
a monofunctional polymerizable liquid crystal compound, a multifunctional polymerizable liquid crystal compound, and reactive non-liquid crystal compound in 5 parts by weight or less with respect to 100 parts by weight of the polymerizable liquid crystal material,
wherein the ratio of multifunctional liquid crystal compound in the polymerizable liquid crystal material is 50 wt % to 90 wt %,
wherein the multifunctional liquid crystal compound comprises a liquid crystal compound having two polymerizable functional groups, and a liquid crystal compound having at least three polymerizable functional groups, and
wherein a weight ratio of the liquid crystal compound having at least three polymerizable functional groups in the polymerizable liquid crystal material is in a range of 8 wt % to 20 wt %.
2. The optical film according to claim 1 , wherein a thickness-direction retardation of the liquid crystal layer with respect to light with a wavelength of 550 nm is from −20 nm to 20 nm.
3. The optical film according to claim 1 , of which a sheet resistance is 10 12 Ω or less.
4. The optical film according to claim 1 , wherein the liquid crystal composition further comprises a non-liquid crystal compound having at least four functional groups capable of reacting with a polymerizable liquid crystal compound.
5. The optical film according to claim 4 , wherein the non-liquid crystal compound has at least four functional groups capable of reacting with the polymerizable liquid crystal compound, and has a molecular weight or weight average molecular weight of 200 to 5,000 or 200 to 1,000.
6. The optical film according to claim 1 , further comprising:
a base layer; and
an alignment layer formed on a surface of the base layer, the liquid crystal layer being on the alignment layer.
7. The optical film according to claim 6 , wherein the alignment layer or the liquid crystal layer has an anti-static agent.
8. The optical film according to claim 1 , further comprising: an anti-static layer.
9. The optical film according to claim 6 , wherein an anti-static agent is included in the alignment layer or the liquid crystal layer, and an anti-static layer is further formed between the base layer and the alignment layer.
10. The optical film according to claim 1 , further comprising:
a polarizing layer disposed on or under the liquid crystal layer.
11. The optical film according to claim 10 , wherein an angle between an absorption axis of the polarizing layer and an optical axis of the liquid crystal layer is in the range of 40 degrees to 50 degrees.
12. A display device, comprising:
the optical film of claim 1 disposed at the outermost side.
13. A display device, comprising:
a polarizing layer disposed at a visible side; and
the optical film of claim 1 , which is disposed at the outside of the polarizing layer.