Liquid crystal display device
It is an object of the present invention to apply a sufficient electrical field to a liquid crystal material in a horizontal electrical field liquid crystal display device typified by an FFS type. In a horizontal electrical field liquid crystal display, an electrical field is applied to a liquid crystal material right above a common electrode and a pixel electrode using plural pairs of electrodes rather than one pair of electrodes. One pair of electrodes includes a comb-shaped common electrode and a comb-shaped pixel electrode. Another pair of electrodes includes a common electrode provided in a pixel portion and the comb-shaped pixel electrode.
1. A liquid crystal display device comprising:
a gate electrode;
a first insulating layer over the gate electrode;
a semiconductor layer over and in contact with a top surface of the first insulating layer, wherein the semiconductor layer overlaps with the gate electrode;
a source electrode over the semiconductor layer, the source electrode electrically connected to the semiconductor layer;
a drain electrode over the semiconductor layer, the drain electrode electrically connected to the semiconductor layer;
a pixel electrode over and in contact with a top surface of the first insulating layer, the pixel electrode electrically connected to one of the source electrode and the drain electrode;
a second insulating layer over the first insulating layer, the semiconductor layer, the source electrode and the drain electrode;
a common electrode over the second insulating layer, the common electrode having a first slit and a second slit;
a liquid crystal layer over the common electrode; and
a common wiring under the first insulating layer, the common wiring electrically connected to the common electrode,
wherein the semiconductor layer comprises an amorphous silicon,
wherein the first slit comprises a region overlapping with the pixel electrode, and the second slit comprises a region not overlapping with the pixel electrode, and
wherein a first portion of the common electrode overlaps with the pixel electrode and a second portion of the common electrode does not overlaps with the pixel electrode.
2. The liquid crystal display device according to claim 1 , wherein the pixel electrode is electrically connected to the one of the source electrode and the drain electrode through a contact hole of an insulating layer.
3. The liquid crystal display device according to claim 1 , wherein the common electrode is in contact with the common wiring.
4. A mobile phone comprising the liquid crystal display device according to claim 1 .
5. A liquid crystal display device comprising:
a gate electrode;
a first insulating layer over the gate electrode;
a semiconductor layer over and in contact with a top surface of the first insulating layer,
wherein the semiconductor layer overlaps with the gate electrode;
a source electrode over the semiconductor layer, the source electrode electrically connected to the semiconductor layer;
a drain electrode over the semiconductor layer, the drain electrode electrically connected to the semiconductor layer;
a pixel electrode over and in contact with a top surface of the first insulating layer, the pixel electrode electrically connected to one of the source electrode and the drain electrode;
a second insulating layer over the first insulating layer, the semiconductor layer, the source electrode and the drain electrode;
a common electrode over the second insulating layer, the common electrode having a first slit and a second slit; and
a liquid crystal layer over the common electrode,
wherein the first slit comprises a region overlapping with the pixel electrode, and the second slit comprises a region not overlapping with the pixel electrode, and
wherein a first portion of the common electrode overlaps with the pixel electrode and a second portion of the common electrode does not overlaps with the pixel electrode.
6. The liquid crystal display device according to claim 5 , wherein the semiconductor layer comprises an amorphous silicon.
7. The liquid crystal display device according to claim 5 , wherein the pixel electrode is electrically connected to the one of the source electrode and the drain electrode through a contact hole of an insulating layer.
8. The liquid crystal display device according to claim 5 , further comprising:
a common wiring under the first insulating layer, the common wiring electrically connected to the common electrode.
9. The liquid crystal display device according to claim 8 , wherein the common electrode is in contact with the common wiring.
10. A mobile phone comprising the liquid crystal display device according to claim 5 .
11. A liquid crystal display device comprising:
a first conductive layer;
a first insulating layer over the first conductive layer;
a semiconductor layer over and in contact with a top surface of the first insulating layer,
wherein the semiconductor layer overlaps with the first conductive layer;
a second conductive layer over the semiconductor layer, the second conductive layer electrically connected to the semiconductor layer;
a third conductive layer over the semiconductor layer, the third conductive layer electrically connected to the semiconductor layer;
a first transparent conductive layer over and in contact with a top surface of the first insulating layer, the first transparent conductive layer electrically connected to one of the second conductive layer and the third conductive layer;
a second insulating layer over the first insulating layer, the semiconductor layer, the second conductive layer and the third conductive layer;
a second transparent conductive layer over the second insulating layer, the second transparent conductive layer having a first slit and a second slit; and
a liquid crystal layer over the second transparent conductive layer,
wherein the first slit comprises a region overlapping with the first transparent conductive layer, and the second slit comprises a region not overlapping with the first transparent conductive layer, and
wherein a first portion of the second transparent conductive layer overlaps with the first transparent conductive layer and a second portion of the second transparent conductive layer does not overlaps with the first transparent conductive layer.
12. The liquid crystal display device according to claim 11 , wherein the semiconductor layer comprises an amorphous silicon.
13. The liquid crystal display device according to claim 11 , wherein the first transparent conductive layer is electrically connected to the one of the second conductive layer and the third conductive layer through a contact hole of an insulating layer.
14. The liquid crystal display device according to claim 11 , further comprising:
a fourth conductive layer under the first insulating layer, the fourth conductive layer electrically connected to the second transparent conductive layer.
15. The liquid crystal display device according to claim 14 , wherein the second transparent conductive layer is in contact with the fourth conductive layer.
16. A mobile phone comprising the liquid crystal display device according to claim 11 .
17. A liquid crystal display device comprising:
a gate electrode;
a first insulating layer over the gate electrode;
a semiconductor layer over and in contact with a top surface of the first insulating layer, wherein the semiconductor layer overlaps with the gate electrode;
a source electrode over the semiconductor layer, the source electrode electrically connected to the semiconductor layer;
a drain electrode over the semiconductor layer, the drain electrode electrically connected to the semiconductor layer;
a pixel electrode over and in contact with a top surface of the first insulating layer, the pixel electrode electrically connected to one of the source electrode and the drain electrode;
a second insulating layer over the pixel electrode, the first insulating layer, the semiconductor layer, the source electrode and the drain electrode;
a common electrode over the second insulating layer, the common electrode having a first slit and a second slit;
a liquid crystal layer over the common electrode; and
a common wiring under the first insulating layer, the common wiring electrically connected to the common electrode,
wherein the first slit comprises a region overlapping with the pixel electrode, and the second slit comprises a region not overlapping with the pixel electrode,
wherein a first portion of the common electrode overlaps with the pixel electrode and a second portion of the common electrode does not overlaps with the pixel electrode, and
wherein the gate electrode and the common wiring comprises a same material.
18. The liquid crystal display device according to claim 17 , wherein the semiconductor layer comprises an amorphous silicon.
19. The liquid crystal display device according to claim 17 , wherein the pixel electrode is electrically connected to the one of the source electrode and the drain electrode through a contact hole of an insulating layer.
20. The liquid crystal display device according to claim 17 , wherein the common electrode is in contact with the common wiring.
21. The liquid crystal display device according to claim 17 , wherein the common electrode is in a first pixel and a second common electrode is in a second pixel adjacent to the first pixel, the common electrode being spaced from the second common electrode.
22. A liquid crystal display device comprising:
a gate electrode;
a first insulating layer over the gate electrode;
a semiconductor layer over and in contact with a top surface of the first insulating layer, wherein the semiconductor layer overlaps with the gate electrode;
a source electrode over the semiconductor layer, the source electrode electrically connected to the semiconductor layer;
a drain electrode over the semiconductor layer, the drain electrode electrically connected to the semiconductor layer;
a pixel electrode over and in contact with a top surface of the first insulating layer, the pixel electrode electrically connected to one of the source electrode and the drain electrode;
a second insulating layer over the pixel electrode, the first insulating layer, the semiconductor layer, the source electrode and the drain electrode;
a common electrode over the second insulating layer, the common electrode having a first slit and a second slit;
a liquid crystal layer over the common electrode; and
a common wiring under the first insulating layer, the common wiring electrically connected to the common electrode,
wherein the semiconductor layer comprises an amorphous silicon,
wherein the first slit comprises a region overlapping with the pixel electrode, and the second slit comprises a region not overlapping with the pixel electrode,
wherein a first portion of the common electrode overlaps with the pixel electrode and a second portion of the common electrode does not overlaps with the pixel electrode,
wherein the pixel electrode comprises a transparent conductive layer,
wherein the common electrode comprises a transparent conductive layer,
wherein the gate electrode and the common wiring comprises a same material,
wherein the common electrode is in a first pixel and a second common electrode is in a second pixel adjacent to the first pixel, the common electrode being spaced from the second common electrode.
23. The liquid crystal display device according to claim 22 , wherein the pixel electrode is electrically connected to the one of the source electrode and the drain electrode through a contact hole of an insulating layer.
24. The liquid crystal display device according to claim 22 , wherein the common electrode is in contact with the common wiring.