Optical film assembly for a display device

1. A liquid crystal display device comprising:

a first member having a first surface and a second surface;

a second member having a third surface and a fourth surface;

a liquid crystal layer positioned between the first member and the second member, wherein the liquid crystal layer generates a phase delay for light passing therethrough;

a voltage application structure for applying a voltage to the liquid crystal layer, wherein the phase delay generated by the liquid crystal layer is varied between (λ/2+α) and α, wherein α has a non-zero value, according to the voltage that is applied; and

a compensation film coupled to at least one of the first member and the second member, wherein the compensation film generates a compensation phase delay of −α,

wherein the device operates in a normally white mode, and wherein the phase delay generated by the liquid crystal layer is (λ/2+α) for a white image when no voltage is applied and α for a black image when the voltage is applied.

2. The device of claim 1 , wherein the device has a transmissive region, and wherein the phase delay in the transmissive region is about (λ/2+α) for the white image when no voltage is applied and is about α for the black image when the voltage is applied.

3. The device of claim 1 , wherein the device has a reflective region with a reflective region phase delay, and wherein the reflective region phase delay is about (λ/2+α)/2 for the white image when no voltage is applied and is about α/2 for the black image when the voltage is applied.

4. A liquid crystal display device comprising:

a first member having a first surface and a second surface;

a second member having a third surface and a fourth surface;

a liquid crystal layer positioned between the first member and the second member, wherein the liquid crystal layer generates a phase delay for light passing therethrough;

a voltage application structure for applying a voltage to the liquid crystal layer, wherein the phase delay generated by the liquid crystal layer is varied between (λ/2+α) and α, wherein α has a non-zero value, according to the voltage that is applied; and

a compensation film coupled to at least one of the first member and the second member, wherein the compensation film generates a compensation phase delay of −α, wherein the device operates in a normally black mode, and wherein the phase delay generated by the liquid crystal layer is α for a black image when no voltage is applied and is (λ/2+α) for a white image when the voltage is applied.

5. The device of claim 4 , wherein the device has a reflective region with a reflective region phase delay, and wherein the reflective region phase delay is about α/2 for the black image when no voltage is applied and is about (λ/2+α)/2 for the white image when the voltage is applied.

6. The device of claim 4 , wherein the device has a transmissive region, and wherein the phase delay generated by the liquid crystal layer is α for the black image when no voltage is applied and (λ/2+α) for the white image when the voltage is applied.

7. A liquid crystal display device comprising:

a first member having a first surface and a second surface;

a second member having a third surface and a fourth surface;

a liquid crystal layer positioned between the first member and the second member, wherein the liquid crystal layer generates a phase delay for light passing therethrough;

a voltage application structure for applying a voltage to the liquid crystal layer, wherein the phase delay generated by the liquid crystal layer is varied between (λ/2+α) and α, wherein α has a non-zero value, according to the voltage that is applied; and

a compensation film coupled to at least one of the first member and the second member, wherein the compensation film generates a compensation phase delay of −α, wherein the phase delay changes by about 10 nm to about 30 nm in response to a change in the voltage by about 0.1 V.

8. The device of claim 7 , wherein λ is about 460 nm to about 550 nm.

9. The device of claim 7 , wherein the value of α is such that:

( Vsu−Vth )/( Vs−Vth )×0.3λ<α<( Vsu−Vth )/( Vs−Vth )×0.7λ, wherein

Vsu is a target operating voltage of the liquid crystal display device;

Vs is an intrinsic saturation voltage of a liquid crystal mixture; and

Vth is an actual threshold voltage of the liquid crystal layer.

10. The device of claim 7 , wherein the liquid crystal layer is homogeneously aligned.

11. The device of claim 7 , wherein the voltage is applied to two electrodes sandwiching the liquid crystal layer.

12. The device of claim 7 , wherein the voltage is applied to two electrodes on a same side of the liquid crystal layer.

13. The device of claim 7 further comprising an optical film assembly, wherein the optical film assembly includes a first film assembly coupled to the first member and a second film assembly coupled to the second member.

14. The device of claim 13 , wherein the compensation film is positioned between the first member and the first film assembly.

15. The device of claim 13 , wherein the compensation film is positioned between the second member and the second film assembly.

16. The device of claim 13 , wherein the optical film assembly comprises:

a polarizer;

a first film for generating a phase shift of λ/2; and

a second film for generating a phase shift of λ/4.

17. The device of claim 7 , wherein the compensation film is a C-plate having a phase shift of α to generate a compensation phase delay of −α.

18. The device of claim 7 , wherein the liquid crystal layer has a first cell gap in the reflective region and a second cell gap in the transmissive region, wherein the first cell gap generates a phase difference of about 140 nm to about 240 nm for λ of about 550 nm.

19. The device of claim 7 , wherein the liquid crystal layer has a first cell gap in the reflective region and a second cell gap in the transmissive region, wherein the second cell gap generates a phase delay of about 280 nm to about 480 nm.