Display device and manufacturing method thereof

A liquid crystal display device comprising:

• a transistor over a first substrate, the transistor comprising a first channel formation region and a second channel formation region in a semiconductor film;
• a first insulating film over the semiconductor film;
• a gate wiring over the first insulating film;
• a first conductive film over the first substrate;
• a second insulating film over the gate wiring and the first conductive film;
• a source line over and in contact with the second insulating film;
• a drain electrode over and in contact with the second insulating film;
• a third insulating film over and in contact with the source line;
• a second conductive film over and in contact with the third insulating film, the second conductive film comprising indium tin oxide;
• a third conductive film over and in contact with the second conductive film, the third conductive film comprising aluminum;
• a fourth conductive film over the second conductive film;
• a liquid crystal layer over the third conductive film;
• and
• a second substrate over the liquid crystal layer,
• wherein the second conductive film comprises a first region which is overlapped with the third conductive film and a second region which is not overlapped with the third conductive film,
• wherein the first region includes a region which overlaps the first conductive film with the third insulating film interposed therebetween,
• wherein the second region overlaps with the first substrate with the third insulating film interposed therebetween,
• wherein the second region has a larger area than the first region in one pixel,
• wherein the third conductive film overlaps the first conductive film in an overlap region,
• wherein a long axis of the third conductive film in the overlap region and a long axis of the first conductive film are in a same direction,
• wherein the semiconductor film comprises a third region whose long axis is provided along a long axis direction of the gate wiring and a fourth region whose long axis is provided along a long axis direction of the source line,
• wherein the fourth region includes a region which is overlapped with the first region, and
• wherein the third region includes a fifth region which is not overlapped with the third conductive film.

A liquid crystal display device comprising:

• a transistor over a first substrate, the transistor comprising a first channel formation region and a second channel formation region in a semiconductor film;
• a first insulating film over the semiconductor film;
• a gate wiring over the first insulating film;
• a first conductive film over the first substrate;
• a second insulating film over the gate wiring and the first conductive film;
• a source line over and in contact with the second insulating film;
• a drain electrode over and in contact with the second insulating film;
• a third insulating film over and in contact with the source line;
• a second conductive film over and in contact with the third insulating film, the second conductive film comprising indium tin oxide;
• a third conductive film over and in contact with the second conductive film, the third conductive film comprising aluminum;
• a fourth conductive film over the second conductive film;
• a liquid crystal layer over the third conductive film;
• and
• a second substrate over the liquid crystal layer,
• wherein the second conductive film comprises a first region which is overlapped with the third conductive film and a second region which is not overlapped with the third conductive film,
• wherein the first region includes a region which overlaps the first conductive film with the second insulating film and the third insulating film interposed therebetween,
• wherein the second region overlaps with the first substrate with the third insulating film interposed therebetween,
• wherein the second region has a larger area than the first region in one pixel,
• wherein the third conductive film overlaps the first conductive film in an overlap region,
• wherein a long axis of the third conductive film in the overlap region and a long axis of the first conductive film are in a same direction,
• wherein the semiconductor film comprises a third region whose long axis is provided along a long axis direction of the gate wiring and a fourth region whose long axis is provided along a long axis direction of the source line,
• wherein the fourth region includes a region which is overlapped with the first region, and
• wherein the third region includes a fifth region which is not overlapped with the third conductive film.

A liquid crystal display device comprising:

• a transistor over a first substrate, the transistor comprising a first channel formation region and a second channel formation region in a semiconductor film;
• a first insulating film over the semiconductor film;
• a gate wiring over the first insulating film;
• a first conductive film over the first substrate;
• a second insulating film over the gate wiring and the first conductive film;
• a source line over and in contact with the second insulating film;
• a drain electrode over and in contact with the second insulating film;
• a third insulating film over and in contact with the source line;
• a second conductive film over and in contact with the third insulating film, the second conductive film comprising indium tin oxide;
• a third conductive film over and in contact with the second conductive film, the third conductive film comprising aluminum;
• a fourth conductive film over the second conductive film;
• a liquid crystal layer over the third conductive film;
• and
• a second substrate over the liquid crystal layer,
• wherein the second conductive film comprises a first region which is overlapped with the third conductive film and a second region which is not overlapped with the third conductive film,
• wherein the first region includes a region which overlaps the first conductive film with the third insulating film interposed therebetween,
• wherein the second region overlaps with the first substrate with the third insulating film interposed therebetween,
• wherein the second region has a larger area than the first region in one pixel,
• wherein the third conductive film overlaps the first conductive film in an overlap region,
• wherein a long axis direction of the third conductive film in the overlap region and a long axis direction of the first conductive film are aligned,
• wherein the semiconductor film comprises a third region whose long axis is provided along a long axis direction of the gate wiring and a fourth region whose long axis is provided along a long axis direction of the source line,
• wherein the fourth region includes a region which is overlapped with the first region, and
• wherein the third region includes a fifth region which is not overlapped with the third conductive film.