Transflective liquid crystal display

• US 7,379,135 B2
• Filed: 05/28/2004
• Issued: 05/27/2008
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: Fujitsu Limited
• Inventors: Lin, Ching-Huan, Tsai, Ching-Yu, Chang, Chih-Ming, Chang, Ting-Jui, Tsai, Meng-Chang
• Primary Examiner(s): Duong; Thoi V.
• Application Number:
  US10/857,292
• Publication Number:
  US 20050264729A1
• Time in Patent Office: 1,460 Days
• Field of Search: 349/114, 349/113, 349/43, 349/143, 349/138, 349/106, 349/38, 349/139, 349/129, 349/123
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer

Abstract

A pixel electrode structure of a transflective liquid crystal display comprises a reflective electrode laid on a surface of the gate-insulating layer, a dielectric layer covering the reflective electrode, and a transmissive electrode on the dielectric layer and connected to the reflective electrode.

Claims

1. A pixel electrode structure for an array substrate of a transflective liquid crystal display, the array substrate including a gate line, a data line, a gate-insulating layer covering the gate line, and a switching device respectively connected to the pixel electrode structure, the gate line and the data line, the pixel electrode structure comprising:

a reflective electrode laid on a surface of the gate-insulating layer, wherein the reflective electrode defines a reflective pixel area;

a dielectric layer covering the reflective electrode; and

a transmissive electrode on a surface of the dielectric layer and electrically connected to the reflective electrode, wherein the transmissive electrode arranged over the dielectric layer substantially uncovers the underlying reflective electrode to define a transmissive pixel area beside the reflective pixel area.

2. The pixel electrode structure according to claim 1, wherein the transmissive electrode is made of a transparent conductive material.

3. The pixel electrode structure according to claim 1, wherein the dielectric layer has a low dielectric constant of about 3.5 or smaller.

4. The pixel electrode structure according to claim 1, wherein the dielectric layer has a thickness of about 1.7 μ

m to 2 μ

m.

5. The pixel electrode structure according to claim 1, wherein the reflective electrode is made of a conductive metallic material.

6. The pixel electrode structure according to claim 1, wherein the transmissive electrode connects to the reflective electrode via a contact hole through the dielectric layer.

7. A transflective liquid crystal display, comprising:

a first substrate;

a second substrate, including a gate line, a gate-insulating layer covering the gate line, a data line, a switching device coupled with the gate line and the data line, and a pixel area;

a pixel electrode structure formed in the pixel area and coupled with the switching device, wherein the pixel electrode structure includes a reflective electrode on a surface of the gate-insulating layer and a transmissive electrode spaced apart from the reflective electrode via a dielectric layer, wherein the reflective electrode defines a reflective pixel area, and the transmissive electrode arranged over the dielectric layer substantially uncovers the underlying reflective electrode to define a transmissive pixel area beside the reflective pixel area; and

a liquid crystal placed between the first and second substrate, wherein the transmissive electrode arranged over the surface of the dielectric layer is electrically connected to the reflective electrode.

8. The transflective liquid crystal display according to claim 7, further comprising a color filter placed at an area overlapping with the pixel area.

9. The transflective liquid crystal display according to claim 8, wherein the color filter includes a thinner section in an area corresponding to the reflective electrode.

10. The transflective liquid crystal display according to claim 7, wherein a protrusion is formed over an inner surface of the first substrate at a location opposite to the reflective electrode.

11. The transflective liquid crystal display according to claim 7, wherein a protrusion is formed over an inner surface of the first substrate at a location opposite to the transmissive electrode.

12. The transflective liquid crystal display according to claim 7, wherein the dielectric layer has a low dielectric constant of about 3.5 or smaller.

13. The transflective liquid crystal display according to claim 7, wherein the dielectric layer has a thickness of about 1.7 μ

m to 2 μ

m.

14. The transflective liquid crystal display according to claim 7, wherein the transmissive electrode is connected to the reflective electrode via a contact hole through the dielectric layer.

15. The transflective liquid crystal display according to claim 7, wherein the pixel electrode structure overlaps an area of the gate line.

16. The transflective liquid crystal display according to claim 7, further comprising a common voltage electrode underlying the pixel electrode structure.

17. The transflective liquid crystal display according to claim 16, wherein a portion of the common voltage electrode uncovered by the reflective electrode is located in an area between the reflective electrode and the transmissive electrode.

18. The transflective liquid crystal display according to claim 16, wherein a portion of the common voltage electrode uncovered by the pixel electrode structure is located in an area between the data line and the pixel electrode structure.

19. The transflective liquid crystal display according to claim 16, wherein a portion of the common voltage electrode uncovered by the pixel electrode structure is located in an area between the pixel electrode structure and the gate line.

20. The transflective liquid crystal display according to claim 7, wherein the dielectric layer interposed between the reflective electrode and the transmissive electrode has a thickness and a dielectric constant configured to regulate a difference of strength between a first electric field generated in the reflective pixel area and a second electric field generated in the transmissive pixel area.