Pixel designs of improving the aperture ratio in an LCD

• US 8,179,490 B2
• Filed: 06/12/2009
• Issued: 05/15/2012
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Lin, Hsiang-Lin, Lin, Ching-Huan, Shih, Chih-Hung, Huang, Wei-Ming
• Primary Examiner(s): Kianni, K. Cyrus
• Application Number:
  US12/483,390
• Publication Number:
  US 20100315569A1
• Time in Patent Office: 1,068 Days
• Field of Search: 349/43, 349/44
• US Class Current: 349/44
• CPC Class Codes: G02F 1/13606 having means for reducing parasitic capacitance
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors

Abstract

This invention in one aspect relates to a pixel structure. In one embodiment, the pixel structure includes a scan line formed on a substrate and a data line formed over the substrate defining a pixel area, a switch formed inside the pixel area on the substrate, a shielding electrode having a first portion and a second portion extending from the first portion, and formed over the scan line, the data line and the switch, where the first portion is overlapped with the switch and the second portion is overlapped with the data line, and a pixel electrode having a first portion and a second portion extending from the first portion, and formed over the shielding electrode in the pixel area, where the first portion is overlapped with the first portion of the shielding electrode so as to define a storage capacitor therebetween and the second portion has no overlapping with the second portion of the shielding electrode.

Claims

1. A pixel structure usable in a liquid crystal display (LCD), comprising:

(a) a scan line formed on a substrate;

(b) a data line formed over the substrate;

(c) a pixel area associated with the scan line and the data line;

(d) a switch formed inside the pixel area on the substrate;

(e) a shielding electrode having a first portion and a second portion extending from the first portion, and formed over the scan line, the data line and the switch, wherein the first portion is overlapped with the switch, and wherein the second portion is overlapped with the data line wherein the first and second portions are formed adjacent and over the switch; and

(f) a pixel electrode having a first portion and a second portion extending from the first portion, and formed over the shielding electrode in the pixel area, wherein the first portion is overlapped with the first portion of the shielding electrode so as to define a storage capacitor therebetween, and wherein the second portion has no overlapping with the second portion of the shielding electrode,

wherein the switch has a gate, a source and a drain electrically connected to the scan line, the data line and the pixel electrode, respectively.

2. The pixel structure of claim 1, further comprising:

(a) a first insulation layer formed between the scan line and the data line;

(b) a second insulation layer formed between the data line and the shielding electrode; and

(c) a third insulation layer formed between the shielding electrode and the pixel electrode.

3. The pixel structure of claim 2, wherein the gate of the switch is formed on the substrate, and the source and drain of the switch are formed between the first insulation layer and the second insulation layer.

4. The pixel structure of claim 3, wherein the switch further comprises a semiconductor layer formed between the source and drain and the first insulation layer.

5. The pixel structure of claim 4, wherein the semiconductor layer comprises a channel layer formed on the first insulation layer and an ohmic contact layer formed on the channel layer.

6. The pixel structure of claim 5, wherein the channel layer is formed of amorphous silicon (a-Si), and wherein the ohmic contact layer is formed of an N⁺ doped or CVD deposited semiconductor.

7. The pixel structure of claim 1, wherein the switch comprises a thin film transistor.

8. The pixel structure of claim 1, wherein the second portion of the shielding electrode is configured to shield the electric field produced from the data line.

9. The pixel structure of claim 1, wherein the shielding electrode is made of an opaque, conductive material.

10. The pixel structure of claim 1, wherein the pixel electrode has a comb-like shape.

11. The pixel structure of claim 1, wherein the pixel electrode is made of a transparent, conductive material.

12. A liquid crystal display (LCD) comprising a plurality of the pixel structures of claim 1, arranged in a matrix.