Fringe field switching mode transflective LCD having slits in the reflective area of a pixel electrode that have an inclination angle greater than slits in the transmissive area by about 10 to 40 degrees

• US 7,525,614 B2
• Filed: 08/30/2005
• Issued: 04/28/2009
• Est. Priority Date: 05/11/2005
• Status: Active Grant

• Current Assignee: Hydis Technology Company Limited (E Ink Holdings Incorporated)
• Original Assignee: Hydis Technology Company Limited (E Ink Holdings Incorporated)
• Inventors: Kim, Hyang Yul, Jeong, Youn Hak, Kim, Kwi Hyun, Park, Jun Baek
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): HEYMAN, JOHN S
• Application Number:
  US11/215,230
• Publication Number:
  US 20060256268A1
• Time in Patent Office: 1,337 Days
• Field of Search: 349/113, 349/114, 349/141
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 2201/122 having a particular pattern

Abstract

Disclosed is a fringe field switching mode transflective liquid crystal display capable of displaying high quality images. The transflective liquid crystal display includes a lower substrate having a counter electrode and a pixel electrode, an upper substrate aligned in opposition to the lower substrate by interposing a liquid crystal layer therebetween, an upper polarizing plate, a lower polarizing plate, a reflective plate provided at an inner portion of the lower substrate, a lower λ/2 plate, and an upper λ/2 plate. An inclination angle, a slit width and a slit interval of the pixel electrode of the reflective area are different from those of the pixel electrode of the transmissive area. The liquid crystal layer presents a phase delay of about 0 to λ/4 in the reflective area and presents a phase delay of about 0 to λ/2 in the transmissive area.

Claims

1. A fringe field switching mode transflective liquid crystal display having a dual cell gap structure, in which a cell gap of a transmissive area is different from a cell gap of a reflective area, the fringe field switching mode transflective liquid crystal display comprising:

a lower substrate having a counter electrode and a pixel electrode embodied as plurality of slits in respective transmissive and reflective areas;

an upper substrate aligned in opposition to the lower substrate;

a liquid crystal layer interposed between the lower and upper substrates;

an upper polarizing plate aligned at an outer portion of the upper substrate;

a lower polarizing plate aligned at an outer portion of the lower substrate;

a reflective plate provided at an inner portion of the lower substrate in the reflective area by interposing an organic resin layer therebetween;

a lower λ

/2 plate provided between the lower substrate having the reflective plate and the lower polarizing plate; and

an upper λ

/2 plate provided between the upper substrate and the upper polarizing plate, wherein an inclination angle, of slits in the pixel electrode formed in the reflective area are, larger than the inclination angle of slits in the pixel electrode formed in the transmissive area by about 10 to 40°

, a phase delay of the liquid crystal layer formed in the reflective area is in a range of about 0 to λ

/4, and a phase delay of the liquid crystal layer formed in the transmissive area in a range of about 0 to λ

/2.

2. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein the slit width and the slit interval of the pixel electrode formed in the reflective area are identical to those of the pixel electrode formed in the transmissive area by less than 2 μ

m.

3. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein a slit width and a slit interval of the pixel electrode formed in the reflective area are smaller than those of the pixel electrode formed in the transmissive area by less than 2 μ

m.

4. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein a phase delay value of the upper and lower λ

/2 plates is about 250 to 400 nm.

5. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein the liquid crystal layer has a phase delay value of about 100 to 200 nm in the reflective area.

6. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein the liquid crystal layer has a phase delay value of about 250 to 400 nm in the transmissive area.

7. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein a transmissive axis of the lower polarizing plate matches with a transmissive axis of the upper polarizing plate, and optical axes of the upper and lower λ

/2 plates are twisted from transmissive axes of the upper and lower polarizing plates at an angle of 15°

.

8. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein the organic resin layer is formed at an upper surface thereof with a plurality of embossing patterns.

9. The fringe field switching mode transflective liquid crystal display as claimed in claim 1, wherein the organic resin layer has a thickness of about 600 to 2000 nm.

10. The fringe field switching mode transflective liquid crystal display as claimed in claim 8, wherein the embossing pattern has a diameter of about 3 to 10 μ

m and a height of about 700 to 800 nm from the upper surface of the organic resin layer.

11. The fringe field switching mode transflective liquid crystal display as claimed in claim 8, wherein a distance between the embossing patterns is at least 2 μ

m.

12. The fringe field switching mode transflective liquid crystal display as claimed in claim 8, wherein the embossing pattern has an inclination angle of about 5 to 15°

.