Reflective liquid crystal display of twisted nematic mode with high reflectance ratio
First Claim
1. A reflective liquid crystal display device, comprising:
- first and second substrates spaced apart and facing each other;
a twisted nematic liquid crystal layer sandwiched between the two substrates, the liquid crystal layer having a twist angle and birefringence property Δ
n and having a thickness d;
a retardation film disposed on the first substrate, a linear polarizer disposed on the retardation film and converting an incident light to a linearly polarized light; and
a reflector disposed between the liquid crystal layer and the second substrate and reflecting light passed through the liquid crystal layer, wherein said twist angle is in a range between above 65° and
75° and
a product dΔ
n is in a range between about 0.20 μ
m and 0.28 μ
m.
3 Assignments
0 Petitions
Accused Products
Abstract
A reflective liquid crystal display device includes: first and second substrates spaced apart and facing each other; a twisted nematic liquid crystal layer sandwiched between the two substrates, the liquid crystal layer having a twist angle and birefringence property Δn and having a thickness d; a retardation film disposed on the first substrate and opposite to the liquid crystal layer, the film converting a first linearly polarized light from above to a first circularly polarized light and converting a second circularly polarized light reflected from below to a second linearly polarized light; a linear polarizer disposed on the retardation film and opposite to the liquid crystal layer and converting the incident light to the first linearly polarized light; and a reflector disposed between the liquid crystal layer and the second substrate and reflecting light passed through the liquid crystal layer. A most desirable range for the twist angle is between above 65° and 75° or 75° and 85° and a most desirable range of a product dΔn is between about 0.20 μm and 0.28 μm or 0.18 μm and 0.26 μm. By the invention, light reflectance, contrast ratio and yield can be enhanced.
21 Citations
21 Claims
-
1. A reflective liquid crystal display device, comprising:
-
first and second substrates spaced apart and facing each other;
a twisted nematic liquid crystal layer sandwiched between the two substrates, the liquid crystal layer having a twist angle and birefringence property Δ
n and having a thickness d;
a retardation film disposed on the first substrate, a linear polarizer disposed on the retardation film and converting an incident light to a linearly polarized light; and
a reflector disposed between the liquid crystal layer and the second substrate and reflecting light passed through the liquid crystal layer, wherein said twist angle is in a range between above 65° and
75° and
a product dΔ
n is in a range between about 0.20 μ
m and 0.28 μ
m.- View Dependent Claims (2, 3, 4)
-
-
5. A reflective liquid crystal display device, comprising:
-
first and second substrates spaced apart and facing each other;
a twisted nematic liquid crystal layer sandwiched between the two substrates, the liquid crystal layer having a twist angle and birefringence property Δ
n and having a thickness d;
a retardation film disposed on the first substrate, a linear polarizer disposed on the retardation film and converting an incident light to a linearly polarized light; and
a reflector disposed between the liquid crystal layer and the second substrate and reflecting light passed through the liquid crystal layer, wherein said twist angle is in a range between about 75° and
85° and
a product dΔ
n is in a range between about 0.2 μ
m and 0.26 μ
m.- View Dependent Claims (6, 7)
-
-
8. A liquid crystal display device, comprising:
-
a first substrate;
a common electrode disposed below said substrate;
a liquid crystal layer disposed below said common electrode, said liquid crystal layer having a twist angle substantially ranging from above 65°
to 75° and
a dΔ
n substantially ranging from 0.20 μ
m and 0.28 μ
m;
a reflective electrode disposed below said liquid crystal layer; and
a second substrate disposed below said reflective electrode. - View Dependent Claims (9, 10, 11, 12, 13, 14)
a retardation film disposed above said first substrate; and
a linear polarizer disposed above said retardation film.
-
-
14. The liquid crystal display device of claim 13, wherein said retardation film is composed of two or more sheets.
-
15. A liquid crystal display device, comprising:
-
a first substrate;
a common electrode disposed below said substrate;
a liquid crystal layer disposed below said common electrode, said liquid crystal layer having a twist angle substantially ranging from 75°
to 85° and
a dΔ
n substantially ranging from 0.20 μ
m and 0.26 μ
m;
a reflective electrode disposed below said liquid crystal layer; and
a second substrate disposed below said reflective electrode. - View Dependent Claims (17, 18, 19)
-
-
16. The liquid crystal display device of 15, wherein said twist angle and said dΔ
- n of said liquid crystal layer substantially are 80° and
0.24 μ
m, respectively.
- n of said liquid crystal layer substantially are 80° and
-
20. The liquid crystal display device of 15, further comprising:
-
a retardation film disposed above said first substrate; and
a linear polarizer disposed above said retardation film. - View Dependent Claims (21)
-
Specification
-
- Resources
-
Current AssigneeLG Display Co., Ltd.
-
Original AssigneeLG Philips LCD Company Limited (LG Display Co., Ltd.)
-
InventorsKim, Woohyun
-
Primary Examiner(s)Ngo, Julie
-
Application NumberUS09/571,276Time in Patent Office1,288 DaysField of Search349/113, 349/96-99, 349/117, 349/119, 349/179, 349/186, 349/180, 349/181US Class Current349/179CPC Class CodesG02F 1/133553 Reflecting elements associa...G02F 1/13363 Birefringent elements, e.g....G02F 2202/40 Materials having a particul...
