Twisted nematic color liquid crystal display

• US 6,295,113 B1
• Filed: 05/17/1999
• Issued: 09/25/2001
• Est. Priority Date: 12/16/1998
• Status: Expired due to Fees

• Current Assignee: Picvue Electronics Limited
• Original Assignee: Picvue Electronics Limited
• Inventors: Yang, Chiu-Lien
• Primary Examiner(s): Dudek, James A.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US09/312,947
• Time in Patent Office: 862 Days
• Field of Search: 349/179, 349/180, 349/181, 349/132, 349/117, 349/113, 349/96
• US Class Current: 349/179
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 1/1396 the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell G02F1/141 takes precedence
• CPC Class Codes: G02F 2202/40 Materials having a particular birefringence, retardation
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

A twisted nematic color liquid crystal display. The liquid crystal display comprises parallel glass substrates covered by a transparent electrode and an alignment film, a twisted nematic liquid crystal between the glass substrates, a retardation layer and polarizers. Between the glass substrates, a liquid crystal unit which forms the liquid crystal has a twist angle about 70 to about 180 about degree while free of an externally applying voltage. A product of anisotropy of refractive index for the twisted nematic liquid crystal Δn and the thickness d thereof, that is, Δn·d, is set in a range between about 1100 Å to about 2000 Å. Without using a passive device such as an external color light source or color filter, a multi-color or full color display is formed by an active controlling method of birefringence of electric field via applying a voltage on the transparent electrode.

Claims

1. A twisted nematic color liquid crystal display, comprising:

a first glass substrate;

a second glass substrate, disposed parallel to the first glass substrate; and

a nematic liquid crystal, between the first and the second glass substrates, wherein nematic liquid crystal has a twist angle of about 70 degree to about 180 degree and a product of refractive index anisotropy and a thickness ranged from about 1100 Å

to about 2000 Å

.

2. The twisted nematic color liquid crystal display according to claim 1, comprising further:

a first transparent electrode, disposed between the first glass substrate and the nematic liquid crystal; and

the second transparent electrode, disposed between the second glass substrate and the nematic liquid crystal display.

3. The twisted nematic color liquid crystal display according to claim 2, comprising further:

a first alignment film, disposed between the first electrode and the nematic liquid crystal display; and

a second alignment film, disposed between the second electrode and the nematic liquid crystal display.

4. The twisted nematic color liquid crystal display according to claim 1, comprising further:

a first polarizer, positioned over a second surface of the first glass substrate opposite to a first surface thereof having the nematic liquid crystal thereon; and

a second polarizer, positioned over a second surface of the glass substrate opposite to a first surface thereof having the nematic liquid crystal thereon.

5. The twisted nematic color liquid crystal display according to claim 4, comprising further a reflection plate, wherein the second polarizer is between the reflection plate and the second glass substrate.

6. The twisted nematic color liquid crystal display according to claim 1, comprising further a retardation layer between the first glass substrate and the nematic liquid crystal.

7. The twisted nematic color liquid crystal display according to claim 6, wherein the retardation layer has a product of refractive index anisotropy and thickness ranged from about 1100 Å

to about 2500 Å

.

8. The twisted nematic color liquid crystal display according to claim 6, comprising further:

a first polarizer, between the retardation layer and the nematic liquid crystal; and

a second polarizer, between the glass substrate and the nematic liquid crystal.

9. The twisted nematic color liquid crystal display according to claim 8, comprising further a reflection plate, disposed on a side of the second polarizer opposite to the other side of the second polarizer facing the nematic liquid crystal.

10. A twisted nematic color liquid crystal display, comprising:

a first and a second polarizers;

a nematic liquid crystal, between the first and the polarizers;

a first glass substrate, between the first polarizer and the nematic liquid crystal;

a second glass substrate, between the second polarizer and the nematic liquid crystal;

a first alignment film, between the first glass substrate and the nematic liquid crystal; and

a second alignment film, between the second glass substrate and the nematic liquid;

wherein

the nematic liquid crystal has a twist angle of about 70 degree to about 180 degree and a product of refractive index anisotropic and thickness of about 1100 Å

to about 2000 Å

.

11. The twist nematic color liquid crystal display according to claim 10, comprising further:

a first transparent electrode, between the first glass substrate and the first alignment film; and

a second transparent electrode, between the second glass substrate and the second alignment film.

12. The twist nematic color liquid crystal display according to claim 10, comprising further a retardation over the first polarization layer.

13. The twist nematic color liquid crystal display according to claim 12, wherein the retardation layer has a product refractive index anisotropy and thickness of about 1100 Å

to about 2500 Å

.

14. The twist nematic color liquid crystal display according to claim 10, comprising further a reflection plate over the second polarizer.