Multi-domain liquid crystal display

Abstract

A multi-domain liquid crystal display includes a first and a second substrates, and a liquid crystal layer is interposed between the first and the second substrates. A first common electrode is formed on an entire surface of the first substrate. A first dielectric layer is formed on the second substrate and covers first signal lines, and a second dielectric layer is formed on the first dielectric layer and covers second signal lines. A plurality of pixel electrodes are formed on the second dielectric layer, and a plurality of second common electrodes are formed on the second substrate, where a voltage difference existing between the second common electrodes and the pixel electrode produces fringe fields.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a schematic diagram illustrating a conventional design of a multi-domain vertically-aligned liquid crystal display.

FIG. 1B shows a schematic diagram illustrating another conventional design of a multi-domain vertically-aligned liquid crystal display.

FIG. 2 shows a schematic diagram illustrating another conventional design of a multi-domain vertically-aligned liquid crystal display.

FIG. 3 shows a cross-section illustrating a multi-domain liquid crystal display according to an embodiment of the invention.

FIG. 4 shows a plan view observed from the normal direction of an array substrate according to an embodiment of the invention.

FIG. 5A shows a cross-sectional view taken along line A-A′ in FIG. 4, and FIG. 5B shows a cross-sectional view taken along line B-B′ in FIG. 4.

FIGS. 6A and 6B show schematic diagrams illustrating the operation principle according to the invention.

FIG. 7 shows a simulation diagram illustrating the distribution of tilted liquid crystal molecules.

FIG. 8 shows a plan view illustrating the distribution of the common electrode sections according to another embodiment of the invention.

FIG. 9 shows a plan view illustrating the distribution of the common electrode sections according to another embodiment of the invention.

FIG. 10 shows a plan view illustrating the distribution of the common electrode sections according to another embodiment of the invention.

FIG. 11 shows a plan view illustrating the distribution of the common electrode sections according to another embodiment of the invention.

FIG. 12 shows a plan view illustrating a transflective pixel structure according to an embodiment of the invention.

FIG. 13 shows a cross-sectional view taken along line C-C′ in FIG. 12.

FIG. 14 shows a plan view illustrating a transflective pixel structure according to another embodiment of the invention.

FIG. 15 shows a cross-sectional view illustrating another embodiment of the invention.

FIG. 16 shows a cross-sectional view illustrating another embodiment of the invention.

FIG. 17 shows a plan view illustrating a transflective pixel structure according to another embodiment of the invention, and FIG. 18 shows a cross-sectional view taken along line D-D′ in FIG. 17.

FIG. 19 shows a cross-sectional view illustrating another embodiment of the invention.

FIG. 20 shows a cross sectional-view illustrating the interconnection between two adjacent pixels according to the embodiment shown in FIG. 19.

FIG. 21 shows a plan view illustrating a transflective pixel structure according to another embodiment of the invention, and FIG. 22 shows a cross-sectional view taken along line E-E′ in FIG. 21.

FIG. 23 shows a plan view illustrating another embodiment of the invention.

FIG. 24 shows a plan view illustrating another embodiment of the invention.

FIG. 25 shows a plan view illustrating another embodiment of the invention.

FIG. 26 shows a plan view illustrating another embodiment of the invention.

FIG. 27 shows a schematic diagram illustrating another embodiment of a multi-domain LCD according to the invention.

Claims

1. A multi-domain liquid crystal display, comprising: a first and a second substrates;a liquid crystal layer having negative dielectric anisotropy interposed between the first and the second substrates;a first common electrode formed on an entire surface of the first substrate;a plurality of first and second signals lines provided on the second substrate, wherein two adjacent first signal lines are intersected with two adjacent second signal lines to define a pixel region;a plurality of switching devices each provided in the vicinity of each intersection of the first and second signal lines;a first dielectric layer formed on the second substrate and covering the first signal lines;a second dielectric layer formed on the first dielectric layer and covering the second signal lines;a plurality of pixel electrodes formed on the second dielectric layer; anda plurality of second common electrodes formed on the second substrate, wherein a voltage difference exists between each second common electrode and each pixel electrode to produce fringe fields.

2. The multi-domain liquid crystal display as claimed in claim 1, wherein each second common electrode includes multiple sections that define at least one enclosed region, with each enclosed region overlapping with the pixel electrode to regulate the orientation of liquid crystal molecules.

3. The multi-domain liquid crystal display as claimed in claim 2, wherein the multiple sections are substantially strip-shaped and parallel to the signal lines to define multiple enclosed regions that are arranged in a single column or in two columns.

4. The multi-domain liquid crystal display 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 multi-domain liquid crystal display as claimed in claim 1, wherein the second common electrodes are made of transparent conductive materials or metallic conductive materials.

6. The multi-domain liquid crystal display as claimed in claim 1, wherein the switching device is a thin film transistor.

7. The multi-domain liquid crystal display as claimed in claim 6, wherein the second common electrodes and the gate of the thin film transistor are formed from a Metal 1 layer.

8. The multi-domain liquid crystal display as claimed in claim 7, wherein different second common electrodes respectively in two adjacent pixel regions are connected with each other through a Metal 2 layer.

9. The multi-domain liquid crystal display as claimed in claim 6, wherein the second common electrodes and the drain and the source of the thin film transistor are formed from a Metal 2 layer.

10. The multi-domain liquid crystal display as claimed in claim 1, wherein the second common electrodes are formed from the same layer as the first signal lines or the second signal lines.

11. The multi-domain liquid crystal display as claimed in claim 1, further comprising a third dielectric layer formed overlying the pixel electrodes, wherein the second common electrodes are formed on the third dielectric layer.

12. The multi-domain liquid crystal display as claimed in claim 11, further comprising a flattened dielectric layer interposed between the second dielectric layer and the pixel electrodes.

13. The multi-domain liquid crystal display as claimed in claim 1, further comprising: a third dielectric layer formed overlying the pixel electrodes; anda reflective layer formed on the third dielectric layer and surrounded by the second common electrodes.

14. The multi-domain liquid crystal display as claimed in claim 1, wherein the overlapped portions between the second common electrodes and the pixel electrodes form a storage capacitor.

15. The multi-domain liquid crystal display as claimed in claim 1, wherein the liquid crystal layer comprises an additive of chiral dopant.

16. The multi-domain liquid crystal display as claimed in claim 1, further comprising: a first polarizer positioned next to the first substrate and opposite to the liquid crystal layer;a second polarizer positioned next to the second substrate and opposite to the liquid crystal layer;a first quarter wavelength plate provided between the first polarizer and the first substrate; anda second quarter wavelength plate provided between the second polarizer and the second substrate.

17. A multi-domain liquid crystal display, comprising: a first and a second substrates;a liquid crystal layer having negative dielectric anisotropy interposed between the first and the second substrates;a common electrode formed on an entire surface of the first substrate;a Metal 1 layer formed on the second substrate and patterned to define first signal lines and the gate of a thin film transistor;a first dielectric layer formed overlying the Metal 1 layer;a Metal 2 layer formed on the first dielectric layer and patterned to define second signal lines and the drain and the source of the thin film transistor;a second dielectric layer formed overlying the Metal 2 layer;a plurality of pixel electrodes formed on the second dielectric layer;a third dielectric layer formed overlying the pixel electrodes; anda Metal 3 layer formed on the third dielectric layer, wherein the Metal 3 layer is patterned to define a first and a, second parts apart from each other, the first part is connected to the common electrode to produce fringe fields, and the second part is surrounded by the first part and formed as a reflective layer.

18. The multi-domain liquid crystal display as claimed in claim 17, wherein the first part of the Metal 3 layer includes multiple sections that define at least one enclosed region, with each enclosed region overlapping with the pixel electrode to regulate the orientation of liquid crystal molecules.

19. The multi-domain liquid crystal display as claimed in claim 18, wherein the multiple sections are substantially strip-shaped and parallel to the first signal lines and the second signal lines to define multiple enclosed regions that are arranged in a single column or in two columns.

20. A multi-domain liquid crystal display, comprising: a first and a second substrates;a liquid crystal layer having negative dielectric anisotropy interposed between the first and the second substrates;a first common electrode formed on an entire surface of the first substrate;a plurality of first and second signals lines provided on the second substrate, wherein two adjacent first signal lines are intersected with two adjacent second signal lines to define a pixel region;a plurality of switching devices each provided in the vicinity of each intersection of the first and second signal lines;a first dielectric layer formed on the second substrate and covering the first signal lines;a second dielectric layer formed on the first dielectric layer and covering the second signal lines;a plurality of pixel electrodes formed on the second dielectric layer; anda plurality of pixel electrodes formed on the second dielectric layer; anda plurality of second common electrodes formed on the second substrate, wherein each second common electrode is divided into a first part and a second part, the first part includes multiple sections to produce fringe fields, and the second part is surrounded by the multiple sections of the first part and formed as a reflective layer.

21. The multi-domain liquid crystal display as claimed in claim 20, wherein the second common electrodes are formed from a Metal 1 layer or a Metal 2 layer.

22. The multi-domain liquid crystal display as claimed in claim 20, wherein the multiple sections of the first part define at least one enclosed region, with each enclosed region overlapping with the pixel electrode to regulate the orientation of liquid crystal molecules.

23. The multi-domain liquid crystal display as claimed in claim 22, wherein the multiple sections are substantially strip-shaped and parallel to the first and second signal lines to define multiple enclosed regions that are arranged in a single column or in two columns.