Liquid crystal display device

• US 20050041182A1
• Filed: 10/04/2004
• Published: 02/24/2005
• Est. Priority Date: 01/29/2001
• Status: Active Grant

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Ono, Kikuo, Oke, Ryutaro, Ochiai, Takahiro, Nakayoshi, Yoshiaki, Kurahashi, Nagatoshi
• Granted Patent: US 7,136,130 B2
• Time in Patent Office: Days
• US Class Current: 349/106
• 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 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• 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 1/136222 Colour filters incorporated in the active matrix substrate
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer

Abstract

In a TFT type liquid crystal display device comprising first and second transparent substrates and a liquid crystal layer which is sandwiched between the first and second substrates, the first substrate includes a plurality of video signal lines, a plurality of scanning signal lines and a plurality of pixel regions which are formed as regions surrounded by the video signal lines and the scanning signal lines, each pixel region includes at least one active element, one pixel electrode and one common electrode, and color filter layers are formed between the pixel electrodes and the liquid crystal layer. The liquid crystal display device is substantially characterized in that the common electrodes are formed as layers above the color filters, the pixel electrodes are formed as layers below the color filters, and the color filters are superposed at least on the whole surfaces of the pixel electrodes in the pixel region.

Claims

1. A liquid crystal display device comprising first and second transparent substrates and a liquid crystal layer which is sandwiched between the first and second substrates, wherein the first substrate includes a plurality of video signal lines, a plurality of scanning signal lines and a plurality of pixel regions which are formed as regions surrounded by the video signal lines and the scanning signal lines, each pixel region includes at least one active element, one pixel electrode and one common electrode, and color filters are formed between the pixel electrodes and the liquid crystal layer, the improvement being characterized in that the common electrodes are formed as layers above the color filters and the pixel electrodes are formed as layers below the color filters, and the color filters are formed to be superposed on at least the entire surfaces of the pixel electrodes in the pixel regions.

2. A liquid crystal display device according to claim 1, wherein an organic flattened film is formed between the color filters and the common electrodes.

3. A liquid crystal display device according to claim 1, wherein the pixel electrodes have a planar shape and the common electrodes have linear regions.

4. A liquid crystal display device according to claim 1, wherein portions of the common electrodes are arranged to be superposed on the video signal lines and also function as the common signal lines.

5. A liquid crystal display device according to claim 1, wherein portions of the common electrodes are arranged to be superposed on the scanning signal lines and also function as the common signal lines.

6. A liquid crystal display device according to claim 1, wherein portions of the common electrodes are arranged to be superposed on the scanning signal lines and the video signal lines and also function as the common signal lines.

7. A liquid crystal display device according to claim 4, wherein the common signal lines which are formed of the common electrodes have at least end surfaces thereof superposed on the pixel electrodes.

8. A liquid crystal display device according to claim 4, wherein the common signal lines which are formed of the common electrodes are made of transparent conductive bodies and have light shielding layers on the active elements.

9. A liquid crystal display device according to claim 4, wherein the common signal lines which are formed of the common electrodes are made of metal.

10. A liquid crystal display device according to claim 1, wherein the pixel electrodes are formed of transparent electrodes.

16. A liquid crystal display device according to claim 2, wherein the pixel electrodes have a planar shape and the common electrodes have linear regions.

11. A liquid crystal display device which includes first and second transparent substrates and a liquid crystal layer which is sandwiched between the first and second substrates, wherein the first substrate includes a plurality of video signal lines, a plurality of scanning signal lines and a plurality of pixel regions which are formed as regions surrounded by the video signal lines and the scanning signal lines, each pixel region includes at least one active element, one pixel electrode and one common electrode, and color filters are formed between the pixel electrodes and the liquid crystal layer, the improvement being characterized in that the common electrodes and the pixel electrodes are formed as layers below the color filters and the color filters are formed to be superposed on at least the entire surfaces of the pixel electrodes and of the common electrodes in the pixel regions.

12. A liquid crystal display device according to claim 11, wherein the common electrodes are made of transparent conductive bodies and formed as layers disposed below the pixel electrodes by way of a gate insulation film.

13. A liquid crystal display device according to claim 11, wherein the common electrodes are formed in a planar shape and the pixel electrodes have linear regions.

14. A liquid crystal display device according to claim 11, wherein the liquid crystal display device includes common signal lines which are formed on the same layer as the scanning signal lines and are spaced apart from the scanning signal lines, and the common signal lines have regions where the common signal lines and the common electrodes are superposed with each other.

15. A liquid crystal display device according to claim 11, wherein a boundary of the color filters between neighboring pixels in the extending direction of the scanning signal lines is positioned on the video signal line, and a light shielding layer is formed between the color filters and the liquid crystal layer such that the light shielding layer is superposed on the boundary portion and the video signal line.