Active matrix type liquid crystal display device

Abstract

An active matrix type liquid crystal display includes a first substrate, a second substrate, and a liquid crystal layer interposed between them. A plurality of common lines are provided on the second substrate, and a first dielectric layer provided with contact holes is fonned on the second substrate and covers the common lines. Capacitor electrodes connected to the common lines via the contact holes are provided on the first dielectric layer, and a second dielectric layer is formed overlying the capacitor electrodes. Pixel electrodes are formed on the second dielectric layer, and each pixel electrode together with each capacitor electrode form a storage capacitor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a plan view illustrating a conventional active matrix display device. FIG. 1B shows a cross-sectional view of the active matrix display device shown in FIG. 1A, taken along line A-A′.

FIG. 2A shows a plan view illustrating another conventional active matrix display device, and FIG. 2B shows a cross-sectional view of the active matrix display device shown in FIG. 2A, taken along line B-B′.

FIG. 3 shows a partial cross-sectional view illustrating an active matrix type liquid crystal display device according to the invention.

FIGS. 4A and 4B show schematic diagrams illustrating an embodiment of a pixel structure of an active matrix display device according to the invention, and FIG. 4C shows an equivalent circuit diagram of one pixel structure according to the invention.

FIG. 5 shows a plan view illustrating another embodiment of the invention.

FIG. 6 shows a plan view illustrating another embodiment of the invention.

Claims

1. An active matrix type liquid crystal display device, comprising: a first substrate;a second substrate facing the first substrate;a liquid crystal layer interposed between the first substrate and the second substrate;a common electrode provided on the first substrate;a plurality of first signal lines and common lines provided on the second substrate;a first dielectric layer formed on the second substrate and covering the first signal lines and the common lines, the first dielectric layer having a plurality of contact holes to expose part of the common lines;a plurality of second signal lines and capacitor electrodes provided on the first dielectric layer, the capacitor electrodes being connected to the common lines via the contact holes;a plurality of switching devices, each of which is provided in the vicinity of each intersection of the first and the second signal lines;a second dielectric layer formed overlying the second signal lines and the capacitor electrodes; anda plurality of pixel electrodes formed on the second dielectric layer; wherein each of the pixel electrodes together with each of the capacitor electrodes form a storage capacitor.

2. The active matrix type liquid crystal display device as claimed in claim 1, wherein the first signal lines are gate lines and the second signal lines are data lines.

3. The active matrix type liquid crystal display device as claimed in claim 1, wherein the first signal lines are data lines and the second signal lines are gate lines.

4. The active matrix type liquid crystal display device as claimed in claim 1, wherein the first dielectric layer is a gate insulation layer and the second dielectric layer is a passivation layer.

5. The active matrix type liquid crystal display device as claimed in claim 1, wherein the first and the second dielectric layers are made from silicon nitride (SiNx), silicon oxide (SiOx) or silicon oxynitride (SiOxNy), and the pixel electrode is made from indium tin oxide (ITO) or indium zinc oxide (IZO).

6. The active matrix type liquid crystal display device as claimed in claim 1, wherein the second dielectric layer is thinner than the first dielectric layer.

7. The active matrix type liquid crystal display device as claimed in claim 1, wherein the switching device is an amorphous silicon thin film transistor (a-Si TFT).

8. The active matrix type liquid crystal display device as claimed in claim 1, wherein the capacitor electrodes function as a light-blocking structure.

9. The active matrix type liquid crystal display device as claimed in claim 1, wherein the capacitor electrode includes at least one strip-shaped section.

10. The active matrix type liquid crystal display device as claimed in claim 9, wherein the strip-shaped section is positioned next to the signal lines.

11. A pixel structure having a storage capacitor, comprising: a Metal 1 layer formed on a transparent substrate and patterned to define common lines, gate lines, and the gate of a thin film transistor;a first dielectric layer formed overlying the Metal 1 layer and having at least one contact hole to expose part of the Metal 1 layer;a Metal 2 layer formed on the first dielectric layer and patterned to define data lines, the drain and the source of the thin film transistor, and a first capacitor electrode of the storage capacitor, the first capacitor electrode being connected to the Metal 1 layer through the contact hole;a second dielectric layer formed overlying the Metal 2 layer; anda pixel electrode formed on the second dielectric layer and functioning as a second capacitor electrode of the storage capacitor.

12. The pixel structure as claimed in claim 11, wherein the first dielectric layer is a gate insulation layer and the second dielectric layer is a passivation layer.

13. The pixel structure as claimed in claim 12, wherein the first capacitor electrode is connected to the common lines via the contact hole formed on the gate insulation layer.

14. The pixel structure as claimed in claim 11, wherein the Metal 1 layer is made from Cr, Ta, or Al/Mo metallic films, and the Metal 2 layer is made from Al/Cr, Al/Ti, Ti, or Mo/Al/Mo metallic films.

15. The pixel structure as claimed in claim 11, wherein the capacitor electrode functions as a light-blocking structure of the pixel structure.

16. The pixel structure as claimed in claim 15, wherein the light-blocking structure includes at least one strip-shaped section positioned next to the data lines.

17. An active matrix substrate, comprising: a plurality of gate lines formed on a transparent substrate;a plurality of data lines formed on the transparent substrate and extending in a direction intersecting a direction in which the gate lines extend;a plurality of switching devices, each of which is provided in the vicinity of each intersections of the gate lines and the data lines;a plurality of common lines formed on the transparent substrate and connected to a common electrode;a first dielectric layer formed overlying the common lines and having a plurality of contact holes to exposed part of the common lines;a light-blocking metallic film formed on the first dielectric layer and connected to the common lines via the contact holes;a second dielectric layer formed overlying the light-blocking metallic film; and a plurality of pixel electrodes formed on the second dielectric layer;wherein each of the pixel electrode together with the light-blocking metallic film form a storage capacitor on the active matrix substrate.

18. The active matrix substrate as claimed in claim 17, wherein the common lines are formed from a Metal 1 layer, and the light-blocking metallic film is formed from a Metal 2 layer.

19. The active matrix substrate as claimed in claim 17, wherein the second dielectric layer is thinner than the first dielectric layer.

20. The active matrix substrate as claimed in claim 17, wherein the light-blocking metallic film includes at least one strip-shaped section positioned next to the data lines.