Liquid crystal display device

1. A liquid crystal display device comprising:

an array substrate including a common electrode, an insulation film disposed on the common electrode, a pixel electrode disposed on the insulation film, opposed to the common electrode and provided with a slit, and a first alignment film disposed on the pixel electrode;

a counter-substrate disposed to be opposed to the array substrate; and

a liquid crystal layer formed of a negative-type liquid crystal material held between the array substrate and the counter-substrate,

wherein the liquid crystal layer includes liquid crystal molecules which are initially aligned at an angle of 10° to 45° to a direction which is perpendicular to a direction of extension of the slit, and

a ratio of a varied luminance to a variation amount of a thickness of the first alignment film is less than or equal to 6.0%.

2. The liquid crystal display device of claim 1 , wherein the first alignment film is in contact with the liquid crystal layer,

the counter-substrate includes a second alignment film which is in contact with the liquid crystal layer, and

the first alignment film and the second alignment film are subjected to alignment treatment in such a manner as to define an initial alignment direction of the liquid crystal molecules.

3. The liquid crystal display device of claim 1 , wherein the array substrate further includes a gate line extending in a first direction and a source line extending in a second direction which is perpendicular to the first direction, and

the slit extends in the second direction.

4. A liquid crystal display device comprising:

an array substrate including a common electrode, an insulation film disposed on the common electrode, a pixel electrode which is disposed on the insulation film, is opposed to the common electrode, and includes a plurality of electrode portions spaced apart by a slit, and a first alignment film disposed on the pixel electrode;

a counter-substrate disposed to be opposed to the array substrate; and

a liquid crystal layer held between the array substrate and the counter-substrate,

wherein the liquid crystal layer is composed of a liquid crystal material having a negative dielectric constant anisotropy,

the liquid crystal layer includes liquid crystal molecules which are initially aligned at an angle of 10° to 45° to a direction which is perpendicular to a direction of extension of the electrode portions, and

a ratio of a varied luminance to a variation amount of a thickness of the first alignment film is less than or equal to 6.0%.

5. The liquid crystal display device of claim 4 , wherein the first alignment film is in contact with the liquid crystal layer,

the counter-substrate includes a second alignment film which is in contact with the liquid crystal layer, and

the first alignment film and the second alignment film are subjected to alignment treatment in such a manner as to define an initial alignment direction of the liquid crystal molecules.

6. The liquid crystal display device of claim 4 , wherein the array substrate further includes a gate line extending in a first direction and a source line extending in a second direction which is perpendicular to the first direction, and

the electrode portions extend in the second direction.

7. The liquid crystal display device of claim 2 , wherein the first alignment film is in contact with the pixel electrode.

8. The liquid crystal display device of claim 7 , wherein the counter-substrate further includes a color filter and an overcoat layer covering the color filter, and

the second alignment film is in contact with the overcoat layer.

9. The liquid crystal display device of claim 3 , wherein the common electrode is arranged directly below the pixel electrode and is arranged directly above the source line.

10. The liquid crystal display device of claim 1 , wherein the angle is set in a range of 19° to 45°.

11. The liquid crystal display device of claim 5 , wherein the first alignment film is in contact with the pixel electrode.

12. The liquid crystal display device of claim 11 , wherein the counter-substrate further includes a color filter and an overcoat layer covering the color filter, and the second alignment film is in contact with the overcoat layer.

13. The liquid crystal display device of claim 6 , wherein the common electrode is arranged directly below the pixel electrode and is arranged directly above the source line.

14. The liquid crystal display device of claim 4 , wherein the angle is set in a range of 19° to 45°.