Electro-optical device

• US 20020060756A1
• Filed: 12/07/2001
• Published: 05/23/2002
• Est. Priority Date: 04/21/2000
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kurashina, Hisaki
• Granted Patent: US 6,597,413 B2
• Time in Patent Office: Days
• US Class Current: 349/39
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals
• 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 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2320/0214 with crosstalk due to leakage current of pixel switch in active matrix panels
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/3225 using an active matrix

Abstract

The present invention provides electro-optical device that can include, on a TFT array substrate, pixel electrodes, TFTs for switching the respective pixel electrodes, and scanning lines and data lines respectively connected to the TFTs. By laminating a capacitive electrode and a capacitive line with an interlayer insulator interposed therebetween, a storage capacitor can be formed in a region overlapping the scanning line in a plan view. This arrangement increases a pixel aperture ratio and the capacitance of the storage capacitor, thereby reducing cross-talk and ghost and presenting a high-quality image display.

Claims

1. An electro-optical device, comprising, on a substrate:

scanning lines and data lines that intersect with each other to form a grid-like pattern;

thin-film transistors, each of the thin-film transistors being connected to one of the scanning lines and one of the data lines;

pixel electrodes respectively connected to the thin-film transistors; and

a storage capacitor laminated above the each of the scanning lines, the storage capacator including a pixel-potential capacitive electrode connected to the pixel electrode and being at a pixel-electrode potential, a fixed-potential capacitive electrode being at a predetermined potential, and a dielectric layer disposed between the pixel-potential capacitive electrode and the fixed-potential capacitive electrode.

2. The electro-optical device according to claim 1, the thin-film transistor including a gate electrode that is formed of part of the scanning line and located over a channel region thereof.

3. The electro-optical device according to claim 1, the thin-film transistor including a gate electrode formed of part of the scanning line and located below a channel region thereof.

4. The electro-optical device according to claim 1, a gate electrode of the thin-film transistor being formed of the same conductive layer as the conductive layer forming the scanning line.

5. The electro-optical device according to claim 1, the gate electrode of the thin-film transistor being formed of a conductive layer different from the conductive layer forming the scanning line.

6. The electro-optical device according to claim 1, the storage capacitor being located over the scanning line on the substrate.

7. The electro-optical device according to claim 1, the storage capacitor being located below the scanning line on the substrate.

8. The electro-optical device according to claim 1, the storage capacitor being located in an interlayer position over the data line on the substrate.

9. The electro-optical device according to claim 1, the storage capacitor being located in an interlayer position between the data line and the scanning line on the substrate.

10. The electro-optical device according to claim 1, one of the fixed-potential capacitive electrode and the pixel-potential capacitive electrode being formed of the same conductive layer as the conductive layer forming the data line.

11. The electro-optical device according to claim 1, the pixel-potential capacitive electrode being located over the fixed-potential capacitive electrode.

12. The electro-optical device according to claim 1, the pixel-potential capacitive electrode being located below the fixed-potential capacitive electrode.

13. The electro-optical device according to claim 1, an interlayer position of the pixel electrode being located over the scanning line on the substrate.

14. The electro-optical device according to claim 1, an interlayer position of the pixel electrode being located below the scanning line on the substrate.

15. The electro-optical device according to claim 1, the storage capacitor being laminated with respect to the scanning line and the data line.

16. The electro-optical device according to claim 1, further comprising a capacitive line which is connected to the fixed-potential capacitive electrode, is formed in at least one of a stripe configuration and a grid configuration on the substrate, and is fixed to a predetermined potential outside an image display area.

17. The electro-optical device according to claim 16, the capacitive line being formed of the same conductive layer as the conductive layer forming the fixed-potential capacitive electrode.

18. The electro-optical device according to claim 16, the capacitive line being formed of a conductive layer different from the conductive layer forming the fixed-potential capacitive electrode.

19. The electro-optical device according to claim 1, the pixel-potential capacitive electrode being formed of an island conductive layer disposed between the thin-film transistor and the pixel electrode.

20. The electro-optical device according to claim 19, ajunction of the island conductive layer with the thin-film transistor being formed in a region corresponding to the data line.

21. The electro-optical device according to claim 19, a junction of the island conductive layer with the pixel electrode being formed in a region corresponding to the data line.

22. The electro-optical device according to claim 19, a junction of the island conductive layer with the pixel electrode being formed in a region corresponding to the scanning line.

23. The electro-optical device according to claim 1, the fixed-potential capacitive electrode being laminated between the scanning line and the pixel-potential capacitive electrode.

24. The electro-optical device according to claim 1, the pixel-potential capacitive electrode being laminated closer to the scanning line than the fixed-potential capacitive electrode is laminated to the scanning line.

25. The electro-optical device according to claim 1, the fixed-potential capacitive electrode being laminated between the data line and the pixel-potential capacitive electrode.

26. The electro-optical device according to claim 1, the pixel-potential capacitive electrode being laminated closer to the data line than the fixed-potential capacitive electrode is laminated to the data line.

27. The electro-optical device according to claim 1, the fixed-potential capacitive electrode including a portion, laminated between the scanning line and the pixel-potential capacitive electrode in a region running along the scanning line on the substrate, and a portion, laminated between the data line and the pixel-potential capacitive electrode in a region running along the data line on the substrate.

28. The electro-optical device according to claim 27, wherein in the region running along the scanning line, the pixel-potential capacitive electrode is formed of at least one of a first conductive layer and a second conductive layer that are laminated with the dielectric layer disposed therebetween while the fixed-potential capacitive electrode is formed of the other of the first and second conductive layers, and wherein in the region running along the data line, the pixel-potential capacitive electrode is formed of the other of the first and second conductive layers while the fixed-potential capacitive electrode is formed of the at least one of the first and second conductive layers.

29. The electro-optical device according to claim 1, one of the pixel-potential capacitive electrode and the fixed-potential capacitive electrode being formed of a pair of electrodes that sandwiches the other of the pixel-potential capacitive electrode and the fixed-potential capacitive electrode from above and from below.

30. The electro-optical device according to claim 29, the fixed-potential capacitive electrode being formed of a pair of electrodes that sandwiches the pixel-potential capacitive electrode from above and from below.

31. The electro-optical device according to claim 1, at least one of the pixel-potential capacitive electrode and the fixed-potential capacitive electrode having a light shielding property.

32. The electro-optical device according to claim 31, the one of the capacitive electrodes having the light shielding property containing a refractory metal.

33. The electro-optical device according to claim 31, the one of the capacitive electrodes having the light shielding property being located over the thin-film transistor on the substrate, and being formed of an upper light shielding film having conductivity and at least partly defining an aperture area of each pixel.

34. The electro-optical device according to claim 33, wherein the scanning line, the data line, and the thin-film transistor do not extend beyond a formation area of the upper light shielding film on the substrate in a plan view.

35. The electro-optical device according to claim 31, the one of the capacitive electrodes having the light shielding property covering at least a channel region of the thin-film transistor.

36. The electro-optical device according to claim 35, the one of the capacitive electrodes having the light shielding property being located below the thin-film transistor on the substrate, and being formed of a conductive, lower light shielding film covering at least the channel region on the substrate if viewed from the substrate.

37. The electro-optical device according to claim 36, the scanning line, the data line, and the thin-film transistor do not extend beyond a formation area of the lower light shielding film on the substrate in a plan view.

38. The electro-optical device according to claim 31, further comprising:

an upper light shielding film that is located over the thin-film transistor on the substrate and that defines at least partly an aperture area of each pixel; and

a lower light shielding film that is located below the thin-film layer on the substrate and that covers at least a channel region of the thin-film transistor if viewed from the substrate,

the one of the capacitive electrodes having the light shielding property being formed of one of the upper light shielding film and the lower light shielding film, and the lower light shielding film not extending beyond a formation area of the upper light shielding film on the substrate in a plan view.

39. The electro-optical device according to claim 1, the pixel-potential capacitive electrode being formed of an extension of a conductive layer forming a drain region of the thin-film transistor.

40. The electro-optical device according to claim 1, the pixel-potential capacitive electrode being formed of an extension of a conductive layer forming the pixel electrode.