Display device
View Patent ↗To make the dimension of an electrostatic protection circuit small with the same maintained high in sensitivity. The electrostatic protection circuit is of the configuration that a first diode and a second diode are connected in series, wherein a semiconductor layer owned by each diode is configured to be sandwiched between a gate electrode and a conductive light shielding film. The light shielding film is formed to overlap with the semiconductor layer and has a wider area than the semiconductor layer. This results in having a gate covering the semiconductor layer from an upper side and a back gate covering the semiconductor layer from a lower side, so that the sensitivity can be maintained high irrespective of decreasing the electrostatic protection circuit in dimension.
1. A display device having an electrostatic protection circuit which is of a configuration that a first diode and a second diode are connected in series between a first connection wire with a first power source voltage applied and a second connection wire with a second power source voltage applied and in which between the first and second diodes, a third connection wire connected to the first and second diodes is formed and is provided with a first terminal and a second terminal; wherein:
the first diode has a first semiconductor layer, a first gate electrode and a conductive first light shielding film, the first gate electrode being connected to the third connection wire, the first light shielding film being formed, as viewed in a plan view, to extend to an overlapping position with the third connection wire and being formed in an overlapping relation with the semiconductor layer to possess a wider area than the semiconductor layer; and
the second diode has a second semiconductor layer, a second gate electrode and a conductive second light shielding film, the second gate electrode being connected to the second connection wire, the second light shielding film being formed, as viewed in a plan view, to extend to an overlapping position with the second connection wire and being formed in an overlapping relation with the semiconductor layer to possess a wider area than the semiconductor layer.
2. The display device according to claim 1 , wherein the first and second power source voltages are supplied from DC power source voltages formed within a display region.
3. The display device according to claim 2 , wherein:
the display device has a scanning line drive circuit having a shift register that operates under two power sources;
the first power source is common to a power source on a high-voltage side for the shift register; and
the second power source is common to a power source on a low-voltage side for the shift register.
4. The display device according to claim 1 , wherein the first terminal is connected to a terminal to which a signal the display device acquires from outside is inputted.
5. The display device according to claim 1 , wherein the second terminal is connected to a video signal line or a scanning line drive circuit.
6. The display device according to claim 1 , wherein a first backing film and a second backing film exist between the semiconductor layer and the light shielding film, wherein the first backing film and the second backing film are insulating films.
7. The display device according to claim 1 , wherein the light shielding film is formed using a metal.
8. The display device according to claim 1 , wherein the light shielding film is formed using the same material as the gate electrode.
9. The display device according to claim 1 , wherein:
the display device has a display region and a frame region around the display region; and
the electrostatic protection circuit is formed in the frame region.
10. The display device according to claim 1 , wherein the display device is a liquid crystal display device.
11. The display device according to claim 1 , wherein the display device is an organic EL display.