General film compensated reflective LCD having LC layer with middle layer satisfying a predetermined relationship between phase retardation and half residual phase depending on an external electric field
View Patent ↗A liquid crystal display having at least one of high contrast ratio, high reflectance, and low color dispersion is disclosed. Based on the total boundary residual retardation, the corresponding compensation film and polar conditions may be calculated. Using the compensation film and polarizer conditions, a general film compensated reflective twisted-nametic liquid crystal display (GF-RTN-LCD) may be obtained.
1. A liquid crystal display, comprising:
a liquid crystal cell comprising a first substrate, a second substrate, and a liquid crystal layer interposed therebetween, and the liquid crystal cell having a twisted angle φ and a half residual phase α depending on an external electric field, wherein the liquid crystal layer comprises a middle layer, a first boundary layer sandwiched between the middle layer and the first substrate, and a second boundary layer sandwiched between the middle layer and the second substrate;
a compensation film disposed on the liquid crystal cell, and having a phase retardation δ in the range of (δ 0 −0.2π)≦δ≦(δ 0 +0.2π) and a slow axis angle θ in the range of 0°≦θ≦180°; and
a polarizer disposed on the compensation film and on an ambient light entrance side and having a polarizer angle β in the range of (β 0 −20°+n·90°)≦β≦(β 0 +20°+n·90°);
wherein the compensation film is sandwiched between the polarizer and the liquid crystal cell,
wherein the phase retardation δ 0 satisfies the following relation:
δ
0
=
atan
(
sin
2
ϕ
+
cos
2
αcos
2
ϕ
sin
αsin2θsin2ϕ
+
sin
2
αcos2θcos
2
ϕ
)
,
and
wherein n is an integer with β 0 satisfies the following relation:
β
0
=
θ
+
1
2
atan
(
-
sin
2
ϕ
+
cos
2
αcos
2
ϕ
sin
δ
0
(
sin
αcos2θsin2ϕ
-
sin
2
αsin2θcos
2
ϕ
)
)
.
2. The liquid crystal display of claim 1 , wherein the liquid crystal cell further comprises a first substrate and an opposing reflective substrate, between which the liquid crystal layer is interposed.
3. The liquid crystal display of claim 2 , wherein the opposing reflective substrate comprises a transflective substrate.
4. The liquid crystal display of claim 3 , further comprising a broadband circular polarizer disposed beneath the transflective substrate.
5. The liquid crystal display of claim 1 , wherein a total residual phase of the liquid crystal cell satisfies the following relation α=2π·ψ/λ; wherein ψ is a residual retardation of each boundary sub-layer and λ is a wavelength of light.
6. A display device, comprising:
a display panel comprising the liquid crystal display of claim 1 ; and
a controller coupled to the display panel to control the display panel to render an image in accordance with an input.
7. A liquid crystal display, comprising:
a liquid crystal cell comprising a first substrate, an opposing reflective substrate, and a liquid crystal layer interposed therebetween, the liquid crystal layer having a twisted angle φ and a half residual phase α depending on an external electric field; the liquid crystal layer comprising a middle layer and at least one boundary layer, wherein a total residual phase of the liquid crystal cell satisfies the following relation α=2π·ψ/λ; wherein ψ is a residual retardation of each boundary sub-layer and λ is a wavelength of light;
a compensation film disposed on the liquid crystal cell and on an ambient light entrance side, and having a phase retardation δ in the range of (δ 0 −0.2π)≦δ≦(δ 0 +0.2π) and a slow axis angle θ in the range of 0°≦θ≦180°; and
a polarizer disposed on the compensation film and having a polarizer angle β in the range of (β 0 −20°+n·90°)≦β≦(β 0 +20°+n·90°);
wherein the compensation film is sandwiched between the polarizer and the liquid crystal cell,
wherein the phase retardation δ 0 satisfies the following relation:
δ
0
=
atan
(
sin
2
ϕ
+
cos
2
αcos
2
ϕ
sin
αsin2θsin2ϕ
+
sin
2
αcos2θcos
2
ϕ
)
;
and
wherein n is an integer with β 0 satisfies the following relation:
β
0
=
θ
+
1
2
atan
(
-
sin
2
ϕ
+
cos
2
αcos
2
ϕ
sin
δ
0
(
sin
αcos2θsin2ϕ
-
sin
2
αsin2θcos
2
ϕ
)
)
.
8. The liquid crystal display of claim 7 , wherein the opposing reflective substrate comprises a transflective substrate.
9. The liquid crystal display of claim 7 , further comprising a broadband circular polarizer disposed beneath the transflective substrate.