Liquid crystal display element and liquid crystal display
The liquid crystal display element uses a liquid crystal composition which has a negative value of dielectric anisotropy (Δε) and is designed to improve light transmittance adjusting an elastic constant, and a liquid crystal display including the liquid crystal display element. The liquid crystal display element uses a liquid crystal composition having a dielectric anisotropy (Δε) of less than −1.5, in which a value of Γ of the liquid crystal composition is 0.3 or less, and the value of Γ is obtained from Equation (2) using measured values of a splay elastic constant (K 11 ) and a bend elastic constant (K 33 ) of the liquid crystal composition and a twist elastic constant (K 22 ) value obtained from Equation (1) using measured values of a threshold voltage (Vth), a bend elastic constant (K 33 ), vacuum permittivity (ε 0 ), a cell gap (d), and a helical pitch (P 0 ). V th = π { 1 - 4 ( K 22 K 33 ) 2 ( d P 0 ) 2 } K 33 ɛ 0 Δɛ ( 1 ) Γ = K 22 K 11 + K 33 ( 2 )
1. A fringe field switching (FFS) liquid crystal display element using a liquid crystal composition having a dielectric anisotropy (Δε) of less than −1.5 and a value of Γ of 0.3 or less, and the FFS liquid crystal display element has a maximum transmittance of 27.30% to 28.32% when the value of Γ is within a range of 0.208 to 0.293 at a driving voltage of 5 to 6 V,
wherein the value of Γ is obtained from the following Equation (2) using a twist elastic constant (K 22 ) value obtained from the following Equation (1) using measured values of a threshold voltage (Vth); a bend elastic constant (K 33 ); a vacuum permittivity (ε 0 ); a cell gap (d); and a helical pitch (P 0 ), and measured values of a splay elastic constant (K 11 ) and the bend elastic constant (K 33 ) with respect to the liquid crystal composition:
V
th
=
π
{
1
-
4
(
K
22
K
33
)
2
(
d
P
0
)
2
}
K
33
ɛ
0
Δɛ
(
1
)
Γ
=
K
22
K
11
+
K
33
.
(
2
)
2. The FFS liquid crystal display element according to claim 1 ,
wherein the value of Γ of the liquid crystal composition is 0.01 to 0.3.
3. The FFS liquid crystal display element according to claim 1 , comprising:
a first transparent insulating substrate and a second transparent insulating substrate disposed to oppose each other;
a liquid crystal layer containing the liquid crystal composition, which is interposed between the first transparent insulating substrate and the second transparent insulating substrate;
for each pixel, a common electrode formed of a transparent conductive material, a plurality of gate wirings and data wirings arranged in a matrix form, a thin-film transistor provided in the vicinity of a crossing portion of the gate wiring and the data wiring, and a pixel electrode which is formed of the transparent conductive material and is driven by the thin-film transistor, on the first transparent insulating substrate; and
alignment films which induce homogeneous alignment and are present between the liquid crystal layer and the first transparent insulating substrate and between the liquid crystal layer and the second transparent insulating substrate, respectively,
wherein the alignment directions of the alignment films are substantially parallel to the surface of the first transparent insulating substrate or the second transparent insulating substrate, and
in order to form an electric field between the pixel electrode and the common electrode, the common electrode is disposed nearer to the first transparent insulating substrate than the pixel electrode and provided on substantially the entire surface of the first transparent insulating substrate.
4. A fringe field switching (FFS) liquid crystal display comprising:
the FFS liquid crystal display element according to claim 1 .