Liquid crystal display device having a compensation film with a phase retardation

1. A liquid crystal display device, comprising:

two substrates;

a liquid crystal layer sandwiched between the two substrates;

two polarizers, wherein the two substrates are between the two polarizers; and

a compensation film provided between one of the polarizers and one of the substrates;

wherein a phase retardation, R 0 , of the compensation film satisfies the following formulae (1)-(3):

1< R 0 (450)/ R 0 (λ 0 )≦1.3,  (1)

1.1≦ R 0 (650)/ R 0 (λ 0 )≦2.1,  (2)

100 nm≦ R 0 (λ 0 )≦240 nm,  (3)

wherein R 0 (450), R 0 (650) and R 0 (λ 0 ) represent the phase retardation of the compensation film at wavelengths of 450 nm, 650 nm, and λ 0 , respectively, and λ 0 =[n e −n o ]×d/k , where 450 nm≦λ 0 ≦650 nm, and where n e and n o represent refractive indices of the liquid crystal layer, d represents a cell gap defined between the two substrates and k is a constant, 0.55≦k≦1.

2. The liquid crystal display device of claim 1 , wherein the phase retardation, R 0 , of the compensation film further satisfies the following formulae (4)-(5):

1≦ R 0 (380)/ R 0 (λ 0 )≦2,  (4)

1.2≦ R 0 (780)/ R 0 (λ 0 )≦2.7,  (5)

wherein R 0 (380) and R 0 (780) represent the phase retardation of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

3. The liquid crystal display device of claim 1 , wherein an optical parameter, Nz, of the compensation film satisfies the following formulae (6)-(8):

1≦ Nz (450)/ Nz (λ 0 )≦1.3,  (6)

1≦ Nz (650)/ Nz (λ 0 )≦3,  (7)

0.1≦ Nz (λ 0 )≦0.5,  (8)

wherein Nz(450), Nz(650) and Nz(λ 0 ) represent the Nz value of the compensation film at wavelengths of 450 nm, 650 nm and λ 0 , respectively, and Nz=[n x −n z ]/[n x −n y ] wherein n x , n y and n z represent 3-dimension refractive indices of the compensation film in axes X, Y, and Z, respectively.

4. The liquid crystal display device of claim 3 , wherein the optical parameter, Nz, of the compensation film further satisfies the following formulae (9)-(10):

1≦ Nz (380)/ Nz (λ 0 )≦2,  (9)

1.2≦ Nz (780)/ Nz (λ 0 )≦2.7,  (10)

wherein Nz(380) and Nz(780) represent the Nz value of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

5. The liquid crystal display device of claim 1 , wherein an optical parameter, Rth, of the compensation film satisfies the following formulae (11)-(13):

1≦ Rth (450)/ Rth (λ 0 )≦1.2,  (11)

1.2≦ Rth (650)/ Rth (λ 0 )≦5,  (12)

10 nm≦ Rth (λ 0 )≦120 nm,  (13)

wherein Rth(450), Rth(650) and Rth(λ 0 ) represent the Rth value of the compensation film at wavelengths of 450 nm, 650 nm and λ 0 , respectively, and Rth=[n x −n z ]xd′, wherein n x and n z represent 3-dimension refractive indices of the compensation film in axes X and Z, respectively, and d′represents a thickness of the compensation film.

6. The liquid crystal display device of claim 5 , wherein the optical parameter, Rth, of the compensation film further satisfies the following formulae (14)-(15):

1≦ Rth (380)/ Rth (λ 0 )≦6,  (14)

1.8≦ Rth (780)/ Rth(λ 0 )≦7.1,  (15)

wherein Rth(380) and Rth(780) represent the Rth value of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

7. The liquid crystal display device of claim 1 , wherein the compensation film is formed by combining at least two compensation films that have different wavelength dispersion properties.

8. A liquid crystal display device, comprising:

two substrates;

a liquid crystal layer sandwiched between the two substrates;

two polarizers respectively provided on outer sides of the two substrates; and

a compensation film provided between the polarizer and the substrate;

wherein the phase retardation of the compensation film satisfies the following formulae (1)-(3), (6)-(8) and (11)-(13):

1< R 0 (450)/ R 0 (λ 0 )≦1.3,  (1)

1.1≦ R 0 (650)/ R 0 (λ 0 )≦2.1  (2)

100 nm≦ R 0 (λ 0 )≦240 nm  (3)

1≦ Nz (450)/ Nz (λ 0 )≦1.3  (6)

1≦ Nz (650)/ Nz (λ 0 )≦3  (7)

0.1≦ Nz (λ 0 )≦0.5  (8)

1≦ Rth (450)/ Rth (λ 0 )≦1.2  (11)

1.2≦ Rth (650)/ Rth (λ 0 )≦5  (12)

10 nm≦ Rth (λ 0 )≦120 nm  (13)

wherein R 0 (450), R 0 (650) and R 0 (λ 0 ) represent the phase retardation of the compensation film at wavelengths of 450 nm, 650 nm and λ 0 , respectively, and λ 0 =[n e −n o ]×d/k, where 450 nm≦λ 0 ≦650 nm, and where n e and n o represent the refractive indices of the liquid crystal, d represents the cell gap defined between the two substrates and k is a constant, 0.55≦k≦1; wherein Nz(450), Nz(650) and Nz(λ 0 ) represent the Nz value of the compensation film at wavelengths of 380 nm, 450 nm, 650 nm and λ 0 respectively, and Nz=[n x −n z ]/[n x −n y ]wherein n x , n y and n z represent the 3-dimension refractive indices of the compensation film in the axes of X, Y and Z respectively;

wherein Rth(450), Rth(650) and Rth(λ 0 ) represent the Rth value of the compensation film at wavelengths of 450 nm, 650 nm and λ 0 respectively, and Rth=[n x −n z ]×d′ wherein n x and n z represent the 3-dimension refractive indices of the compensation film in the axes of X and Z respectively and d′ represents the thickness of the compensation film.

9. The liquid crystal display device of claim 8 , wherein the phase retardation of the compensation film further satisfies the following formulae (4)-(5):

1≦ R 0 (380)/ R 0 (λ 0 )≦2,  (4)

1.2≦ R 0 (780)/ R 0 (λ 0 )≦2.7,  (5)

wherein R 0 (380) and R 0 (780) represent the phase retardation of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

10. The liquid crystal display device of claim 8 , wherein the phase retardation of the compensation film further satisfies the following formulae (9)-(10):

1≦ Nz (380)/ Nz (λ 0 )≦2,  (9)

1.2≦ Nz (780)/ Nz (λ 0 )≦2.7,  (10)

wherein Nz(380) and Nz(780) represent the Nz value of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

11. The liquid crystal display device of claim 8 , wherein the phase retardation of the compensation film further satisfies the following formulae (14)-(15):

1≦ Rth (380)/ Rth (λ 0 )≦6,  (14)

1.8≦ Rth (780)/ Rth (λ 0 )≦7.1,  (15)

wherein Rth(380) and Rth(780) represent the Rth value of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

12. The liquid crystal display device of claim 8 , wherein the compensation film is formed by combining at least two compensation films that have different wavelength dispersion properties.

13. A liquid crystal display (LCD) device, comprising:

an LCD unit having a liquid crystal layer; and

a compensation film provided next to the LCD unit and having a phase retardation, R 0 , that satisfies:

1< R 0 (450)/ R 0 (λ 0 )≦1.3,

1.1≦ R 0 (650)/ R 0 (λ 0 )≦2.1,

100 nm≦ R 0 (λ 0 )≦240 nm,

wherein R 0 (450), R 0 (650), and R 0 (λ 0 ) represent the phase retardation of the compensation film at wavelengths of 450 nm, 650 nm, and λ 0 , respectively, and λ 0 [n e −n o ]×d/k, where 450 nm≦λ 0 ≦650 nm, and where n e and n o represent refractive indices of the liquid crystal layer, d represents a cell gap in the LCD unit, and k is a constant, 0.55≦k≦1.

14. The LCD device of claim 13 , further comprising polarizers, wherein the LCD unit and compensation film are provided between the polarizers.

15. The LCD device of claim 13 , wherein the phase retardation of the compensation film further satisfies:

1≦ R 0 (380)/ R 0 (λ 0 )≦2,

1.2≦ R 0 (780)/ R 0 (λ 0 )≦2.7,

wherein R 0 (380) and R 0 (780) represent the phase retardation of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

16. The LCD device of claim 13 , wherein an optical parameter, Nz, of the compensation film satisfies:

1≦ Nz (450)/ Nz (λ 0 )≦1.3,

1≦ Nz (650)/ Nz (λ 0 )≦3,

0.1≦ Nz (λ 0 )≦0.5,

wherein Nz(450), Nz(650) and Nz(λ 0 ) represent the Nz value of the compensation film at wavelengths of 450 nm, 650 nm and λ 0 , respectively, and Nz=[n x −n z ]/[n x −n y ], wherein n x , n y and n z represent 3-dimension refractive indices of the compensation film in axes X, Y, and Z respectively.

17. The LCD device of claim 16 , wherein the optical parameter, Nz, of the compensation film further satisfies:

1≦ Nz (380)/ Nz (λ 0 )≦2,

1.2≦ Nz (780)/ Nz (λ 0 )≦2.7,

wherein Nz(380) and Nz(780) represent the Nz value of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

18. The LCD device of claim 13 , wherein an optical parameter, Rth, of the compensation film satisfies:

1≦ Rth (450)/ Rth (λ 0 )≦1.2,

1.2≦ Rth (650)/ Rth (λ 0 )≦5,

10 nm Rth (λ 0 )≦120 nm,

wherein Rth(450), Rth(650) and Rth(λ 0 ) represent the Rth value of the compensation film at wavelengths of 450 nm, 650 nm and λ 0 , respectively, and Rth=[n x −n z ]xd′, wherein n x and n z represent 3-dimension refractive indices of the compensation film in axes X and Z, respectively, and d′ represents a thickness of the compensation film.

19. The LCD device of claim 18 , wherein the optical parameter, Rth, of the compensation film further satisfies:

1≦ Rth (380)/ Rth (λ 0 )≦6,

1.8≦ Rth (780)/ Rth (λ 0 )≦7.1,

wherein Rth(380) and Rth(780) represent the Rth value of the compensation film at wavelengths of 380 nm and 780 nm, respectively.

20. The LCD device of claim 13 , wherein the LCD unit has two substrates, wherein the liquid crystal layer is between the two substrates, and wherein d represents the cell gap between the substrates.