Liquid crystal display device

1. A liquid crystal display device, comprising:

at least two insulating layers formed on a first conductive layer;

a second conductive layer formed between the at least two insulating layers;

a first contact hole penetrating an upper insulating layer of the at least two insulating layers and exposing a portion of the second conductive layer;

a second contact hole penetrating the at least two insulating layers and exposing a portion of the first conductive layer; and

a contact part comprising a bridge electrode formed of a third conductive layer to electrically connect the first conductive layer to the second conductive layer through the first and second contact holes,

wherein the second contact hole comprises an internal hole penetrating the at least two insulating layers and an external hole surrounding the internal hole and formed in the upper insulating layer,

wherein the internal hole of the second contact hole and the external hole of the second contact hole are separated from each other by a given distance,

wherein the first contact hole and the external hole of the second contact hole have a gently sloping surface as compared to a sloping surface of the internal hole of the second contact hole.

2. The liquid crystal display device according to claim 1 , wherein the external hole of the second contact hole is further extended toward the first contact hole than in another direction.

3. The liquid crystal display device according to claim 2 , wherein a sloping surface of the external hole adjacent to the first contact hole is more gently formed than other sloping surfaces of the external hole.

4. The liquid crystal display device according to claim 3 , wherein the contact part is formed on a thin film transistor substrate comprising an image display unit consisting of a plurality of subpixels and comprising a driving circuit for driving the image display unit.

5. The liquid crystal display device according to claim 4 , wherein the image display unit comprises a pixel electrode formed in a subpixel region, a thin film transistor connected to the pixel electrode, a gate line for controlling the thin film transistor, and a data line for supplying data to the thin film transistor, and wherein the driving circuit comprises a gate driving circuit for driving the gate line.

6. The liquid crystal display device according to claim 5 , wherein the first conductive layer comprises a gate metal layer formed on an insulating substrate, the second conductive layer comprises a source/drain metal layer formed on a lower insulating layer of the at least two insulating layers covering the gate metal layer, and the third conductive layer comprises a transparent conductive layer formed on the upper insulating layer covering the source/drain metal layer, wherein the lower insulating layer is a gate insulating layer and the upper insulating layer is a passivation layer.

7. The liquid crystal display device according to claim 6 , wherein the source/drain metal layer comprises double metal layers in which at least an aluminum layer and a molybdenum layer are stacked, and the molybdenum layer is connected to the bridge electrode.

8. The liquid crystal display device according to claim 7 , wherein the image display unit further comprises a storage line formed of the gate metal layer, and wherein the source electrode that is formed of the source/drain metal layer and is extended from the thin film transistor to overlap the storage line with the gate insulating layer disposed therebetween and is connected to the pixel electrode formed of the transparent conductive layer through a third contact hole penetrating the passivation layer.