Liquid crystal display device
A liquid crystal display device (LCD) including an OCB mode liquid crystal layer is provided, in which an even number of domains are formed in one unit pixel, the number of domains being at least two, and the arrangement of liquid crystal (LC) molecules in the domains is controlled so that the LCD has wide vertical and horizontal viewing angles. Also, a disclination line formed in the unit pixel allows the LC molecules to readily make a transition to an initial bend phase.
1. A liquid crystal display device comprising:
a first substrate including a first alignment layer and a first electrode disposed on one surface thereof;
a second substrate opposite to the first substrate and including a second alignment layer and a second electrode disposed on one surface thereof; and
an optically compensated bend (OCB) mode liquid crystal layer disposed between the first and second substrates and including an even number of rubbed domains in one unit pixel, the even number of the rubbed domains in the one unit pixel being at least two, wherein liquid crystal molecules in two adjacent ones of the rubbed domains are arranged in directions perpendicular to each other, the directions of the rubbed domains that are perpendicular to each other being defined through rubbing,
wherein one of the domains has one alignment direction among a first alignment direction corresponding to rubbing the first alignment layer from an upper-left end of the unit pixel toward a lower-right end thereof, a second alignment direction corresponding to rubbing the first alignment layer from a lower-left end of the unit pixel toward an upper-right end thereof, a third alignment direction corresponding to rubbing the first alignment layer from the upper-right end toward the lower-left end, and a fourth alignment direction corresponding to rubbing the first alignment layer from the lower-right end toward the upper-left end; and
wherein corresponding domains respectively formed on the first alignment layer and the second alignment layer are rubbed in a same direction.
2. The device according to claim 1 , wherein each of the first and second alignment layers provides a pretilt angle of 5° to 20° to the liquid crystal molecules of the liquid crystal layer.
3. The device according to claim 1 , wherein each of the first and second alignment layers has a thickness of 500 to 1000 Å.
4. The device according to claim 1 , further comprising:
a first polarizer disposed on the other surface of the first substrate; and
a biaxial compensation film and a second polarizer disposed on the other surface of the second substrate.
5. The device according to claim 4 , wherein the first and second polarizers have polarization axes perpendicular to each other.
6. The device according to claim 1 , wherein the liquid crystal layer has a thickness of 1.5 to 2.5 μm.
7. The device according to claim 1 , wherein the liquid crystal layer includes liquid crystals with positive dielectric anisotropy.
8. The device according to claim 1 , wherein the first electrode is formed of a transparent conductive material.
9. The device according to claim 1 , wherein the first electrode is formed of one selected from an indium tin oxide (ITO) and an indium zinc oxide (IZO).
10. The device according to claim 1 , wherein the first electrode has a thickness of 1000 to 3000 Å.
11. The device according to claim 1 , further comprising a light source device disposed on the other surface of the first substrate.
12. The device according to claim 11 , wherein the light source device includes a reflector sheet, a diffuser sheet, and a light emitting diode (LED).
13. The device according to claim 12 , wherein the LED comprises a red (R) LED, a green (G) LED and/or a blue (B) LED.
14. The device according to claim 12 , wherein the LED is a white (W) LED.
15. The device according to claim 1 , further comprising a color filter interposed between the second electrode and the second substrate.
16. The device according to claim 1 , wherein the liquid crystal molecules comprise OCB mode liquid crystals.