Display device including protective circuit

A display device comprising:na scan line and a signal line intersecting with each other over a substrate having an insulating surface;a pixel portion including a pixel electrode and a transistor, wherein the transistor comprises:na gate electrode electrically connected to the scan line;a channel formation region including a fourth oxide semiconductor layer;a first wiring layer electrically connected to the signal line and the fourth oxide semiconductor layer; anda second wiring layer electrically connected to the pixel electrode and the fourth oxide semiconductor layer;a non-linear element between the pixel portion and a signal input terminal disposed at a periphery of the substrate, wherein the non-linear element comprises:na gate electrode electrically connected to the scan line or the signal line;a gate insulating layer covering the gate electrode;a second oxide semiconductor layer over the gate insulating layer;a third oxide semiconductor layer over the gate insulating layer;a first conductive layer over the gate insulating layer with the second oxide semiconductor layer positioned therebetween;a second conductive layer over the gate insulating layer with the third oxide semiconductor layer positioned therebetween; anda first oxide semiconductor layer in contact with a top surface and a side surface of each of the first conductive layer and the second conductive layer,wherein the second conductive layer of the non-linear element is electrically connected to the gate electrode via a third wiring layer, andwherein a part of the second conductive layer is surrounded by the first conductive layer when seen from above.

A display device comprising:na scan line and a signal line intersecting with each other over a substrate having an insulating surface;a pixel portion including a pixel electrode and a transistor, wherein the transistor comprises:na gate electrode electrically connected to the scan line;a channel formation region including a fourth oxide semiconductor layer;a first wiring layer electrically connected to the signal line and the fourth oxide semiconductor layer; anda second wiring layer electrically connected to the pixel electrode and the fourth oxide semiconductor layer;a protective circuit including a non-linear element over the substrate and outside the pixel portion, wherein the protective circuit connects the scan line and a common wiring to each other or connects the signal line and the common wiring to each other, and wherein the non-linear element comprises:na gate electrode;a gate insulating layer covering the gate electrode;a second oxide semiconductor layer over the gate insulating layer;a third oxide semiconductor layer over the gate insulating layer;a first conductive layer over the gate insulating layer with the second oxide semiconductor layer positioned therebetween;a second conductive layer over the gate insulating layer with the third oxide semiconductor layer positioned therebetween; anda first oxide semiconductor layer in contact with a top surface and a side surface of each of the first conductive layer and the second conductive layer,wherein the second conductive layer is electrically connected to the gate electrode of the non-linear element via a third wiring layer, andwherein a part of the second conductive layer is surrounded by the first conductive layer when seen from above.

A display device comprising:na protective circuit including a non-linear element over a substrate, wherein the non-linear element comprises:na gate electrode;a gate insulating layer covering the gate electrode;a second oxide semiconductor layer over the gate insulating layer;a third oxide semiconductor layer over the gate insulating layer;a first conductive layer over the gate insulating layer with the second oxide semiconductor layer positioned therebetween;a second conductive layer over the gate insulating layer with the third oxide semiconductor layer positioned therebetween; anda first oxide semiconductor layer in contact with a top surface and a side surface of each of the first conductive layer and the second conductive layer,wherein the second conductive layer is electrically connected to the gate electrode of the non-linear element via a wiring layer, andwherein a part of the second conductive layer is surrounded by the first conductive layer when seen from above.