Thin film transistor and display panel having the same
View Patent ↗A thin film transistor includes a gate part which includes a gate electrode and a light blocking electrode extending from the gate electrode. The light blocking electrode prevents a light provided from beneath the gate electrode from being guided to a semiconductor layer. The light blocking electrode is overlapped by two source electrodes and a drain electrode arranged between the two source electrodes, all of which have an I-shape. The width of the light blocking electrode is selected so that a parasitic capacitance between a source part and the gate part may be controlled. Thus, a photocurrent of the thin film transistor may be reduced, and a kickback voltage difference between pixels in the display panel may also be reduced.
1. A thin film transistor comprising:
a gate part including a gate electrode;
a gate insulating layer covering the gate part;
a semiconductor layer arranged on the gate insulating layer corresponding to a region in which the gate electrode is formed;
a source part arranged on the semiconductor layer and intersecting with the gate electrode; and
a drain part intersecting with the gate electrode, the drain part being spaced apart from the source part by a predetermined distance, and
wherein the gate part further includes first and second light blocking electrodes that extend from first and second sides of the gate electrode, respectively, the first and second sides of the gate electrode are arranged in parallel with each other and extend in a first direction, and each of the first and second light blocking electrodes intersects with the source part and the drain part.
2. The thin film transistor of claim 1 , wherein the source part comprises:
a first source electrode and a second source electrode extending in a second direction that is substantially perpendicular to the first direction, and wherein the first and second source electrodes intersect with the first and second sides of the gate electrode and with the first and second portions of the light blocking electrode, the first and second source electrodes being spaced apart from each other by a predetermined distance; and
a connecting electrode arranged in a peripheral area of the gate part to connect the first source electrode and the second source electrode.
3. The thin film transistor of claim 2 , wherein a distance between a side of the semiconductor layer and a side of the light blocking electrode that is adjacent to and parallel with the side of the semiconductor layer is greater than a distance between the side of the semiconductor layer and a side of the gate electrode that is adjacent to and parallel with the side of the semiconductor layer, and further wherein the light blocking electrode blocks a light coming from a side of the gate electrode which is opposite the semiconductor layer from reaching the semiconductor layer.
4. The thin film transistor of claim 2 , wherein the connecting electrode is spaced apart from the gate electrode and the light blocking electrode.
5. The thin film transistor of claim 2 , further comprising pixel electrode, and wherein the drain part extends in the second direction and intersects with the first and second sides of the gate electrode and the first and second portions of light blocking electrode, and the drain part comprises a drain electrode electrically connected with the pixel electrode and positioned between the first source electrode and the second source electrode.
6. The thin film transistor of claim 5 , wherein the drain electrode, the first source electrode, and the second source electrode are extended in parallel with each other, and further wherein each have an I-shape in a location intersecting the gate electrode.
7. The thin film transistor of claim 5 , wherein the light blocking electrode has a width smaller than a length of the two sides of the gate electrode.
8. The thin film transistor of claim 7 , wherein a sum of an overlap area between the light blocking electrode and the first source electrode and an overlap area between the light blocking electrode and the second source electrode is greater by two times than an overlap area between the light blocking electrode and the drain electrode.
9. The thin film transistor of claim 7 , wherein a sum of an overlap area between the light blocking electrode and the first source electrode and an overlap area between the light blocking electrode and the second source electrode is equal to or smaller than an overlap area between the light blocking electrode and the drain electrode.
10. A thin film transistor comprising:
a gate part including a gate electrode, and first and second light blocking electrodes that extend from first and second sides of the gate electrode, respectively, the first and second sides of the gate electrode being arranged in parallel with each other and extending in a first direction, the gate electrode further comprising third and fourth sides;
a gate insulating layer covering the gate part;
a semiconductor layer arranged on the gate insulating layer corresponding to a region in which the gate electrode is formed;
a source part including at least one source electrode that is arranged on the semiconductor layer and extended longer than the third and fourth sides of the gate electrode in a second direction that is substantially perpendicular to the first direction, the source part overlapping the gate electrode, the first light blocking electrode, and the second light blocking electrode; and
a drain part including a drain electrode that is arranged on the semiconductor layer and extended in the second direction for a distance longer than the third and fourth sides of the gate electrode and overlapping the gate electrode, the first light blocking electrode, and the second light blocking electrode, the drain electrode being spaced apart from the source electrode by a predetermined distance.
11. The thin film transistor of claim 10 , wherein each of the first and second light blocking electrodes has a width that is smaller than a length of the two sides of the gate electrode.
12. The thin film transistor of claim 11 , wherein a sum of an overlap area between the first light blocking electrode and the source electrode and an overlap area between the second light blocking electrode and the source electrode is greater by two times than a sum of an overlap area between the first light blocking electrode and the drain electrode and an overlap area between the second light blocking electrode and the drain electrode.
13. The thin film transistor of claim 11 , wherein a sum of an overlap area between the first light blocking electrode and the source electrode and an overlap area between the second light blocking electrode and the source electrode is equal to or smaller than a sum of an overlap area between the first light blocking electrode and the drain electrode and an overlap area between the second light blocking electrode and the drain electrode.
14. A display panel comprising:
a first base substrate;
a plurality of data lines arranged on the first base substrate;
a plurality of gate lines intersecting with the data lines to define a plurality of pixel areas;
a plurality of thin film transistors arranged in the pixel areas;
a plurality of pixel electrodes arranged in the pixel areas and connected to a corresponding thin film transistor; and
a second base substrate facing the first base substrate,
each thin film transistor comprising:
a gate part including a gate electrode;
a gate insulating layer covering the gate part;
a semiconductor layer arranged on the gate insulating layer corresponding to a region in which the gate electrode is formed;
a source part arranged on the semiconductor layer and overlapped with the gate electrode; and
a drain part overlapped with the gate electrode and spaced apart from the source part by a predetermined distance,
wherein the gate part further includes first and second light blocking electrodes that extend from first and second sides of the gate electrode, respectively, the first and second sides of the gate electrode are arranged in parallel with each other and extend in a first direction, and each of the first and second light blocking electrodes intersects with the source part and the drain part.
15. The display panel of claim 14 , wherein the source part comprises:
a first source electrode and a second source electrode that are extended in a direction that is substantially perpendicular to the two sides of the gate electrode and allowed to be intersected with the gate electrode and the light blocking electrode, and the first and second source electrodes being spaced apart from each other in a direction that is substantially parallel with the two sides of the gate electrode by a predetermined distance; and
a connecting electrode arranged in a peripheral area of the gate part to connect the first source electrode and the second source electrode.
16. The display panel of claim 15 , wherein a horizontal distance between a side of the semiconductor layer and a side of the light blocking electrode that are adjacent to each other in parallel is greater than a horizontal distance between the side of the semiconductor layer and a side of the gate electrode that are adjacent to each other in parallel, and the light blocking electrode prevents a light provided from a lower portion of the gate electrode from being input to the semiconductor layer.
17. The display panel of claim 15 , wherein the drain part comprises a drain electrode extended in the direction that is substantially perpendicular to the two sides of the gate electrode and allowed to be intersected with the gate electrode and the light blocking electrode, and the drain electrode being arranged between the first source electrode and the second source electrode.
18. The display panel of claim 17 , wherein the light blocking electrode has a width that is smaller than a length of the two sides of the gate electrode.
19. The display panel of claim 18 , wherein a sum of an overlap area between the light blocking electrode and the first source electrode and an overlap area between the light blocking electrode and the second source electrode is equal to or smaller than an overlap area between the light blocking electrode and the drain electrode.
20. The display panel of claim 17 , wherein the first and second source electrodes are branched from a corresponding data line of the data lines, the gate electrode is branched from a corresponding gate line of the gate lines, and the drain electrode is electrically connected to a corresponding pixel electrode of the pixel electrodes.