Display device

Abstract

A protective circuit includes a non-linear element which includes a gate electrode, a gate insulating layer covering the gate electrode, a first oxide semiconductor layer overlapping with the gate electrode over the gate insulating layer, and a first wiring layer and a second wiring layer whose end portions overlap with the gate electrode over the first oxide semiconductor layer and in which a conductive layer and a second oxide semiconductor layer are stacked. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be reduced and the characteristics of the non-linear element can be improved.

1 . A display device comprising:
 a pixel portion over a first substrate;   a transistor included in the pixel portion, the transistor comprising an oxide semiconductor layer including a channel formation region, wherein the oxide semiconductor layer comprises indium, zinc and oxygen;   a first insulating film over the transistor;   a second insulating film comprising silicon nitride over the first insulating film;   a third insulating film comprising an organic material over the second insulating film;   a light-transmitting conductive layer over the third insulating film;   a second substrate over the first substrate; and   a sealing material between the first substrate and the second substrate, wherein the sealing material is provided to surround the pixel portion,   wherein the sealing material is overlapped with the first insulating film and the second insulating film;   wherein the sealing material is in contact with the second insulating film, and   wherein the sealing material is not overlapped with the third insulating film.   
     
     
         2 . The display device according to  claim 1 , wherein the first insulating film comprises silicon oxide. 
     
     
         3 . The display device according to  claim 1 , wherein the organic material is acrylic. 
     
     
         4 . The display device according to  claim 1 , wherein the light-transmitting conductive layer comprises one of indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium tin oxide, indium zinc oxide, and indium tin oxide to which silicon oxide is added. 
     
     
         5 . The display device according to  claim 1 , further comprising a light-emitting element electrically connected to the transistor. 
     
     
         6 . A display device comprising:
 a pixel portion over a first substrate;   a transistor included in the pixel portion, the transistor comprising:
 a gate electrode; 
 a gate insulating layer over the gate electrode; and 
 an oxide semiconductor layer including a channel formation region over the gate insulating layer, wherein the oxide semiconductor layer comprises indium, zinc and oxygen, 
   a first insulating film comprising silicon oxide over the transistor, wherein the first insulating film is in contact with the oxide semiconductor layer;   a second insulating film comprising silicon nitride over the first insulating film;   a third insulating film comprising an organic material over the second insulating film;   a light-transmitting conductive layer over the third insulating film;   a second substrate over the first substrate; and   a sealing material between the first substrate and the second substrate, wherein the sealing material is provided to surround the pixel portion,   wherein the sealing material is overlapped with the first insulating film and the second insulating film;   wherein the sealing material is in contact with the second insulating film, and   wherein the sealing material is not overlapped with the third insulating film.   
     
     
         7 . The display device according to  claim 6 , wherein the organic material is acrylic. 
     
     
         8 . The display device according to  claim 6 , wherein the light-transmitting conductive layer comprises one of indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium tin oxide, indium zinc oxide, and indium tin oxide to which silicon oxide is added. 
     
     
         9 . The display device according to  claim 6 , further comprising a light-emitting element electrically connected to the transistor. 
     
     
         10 . A display device comprising:
 a pixel portion over a first substrate;   a transistor included in the pixel portion, the transistor comprising an oxide semiconductor layer including a channel formation region, wherein the oxide semiconductor layer comprises indium, zinc and oxygen;   a first insulating film over the transistor;   a second insulating film comprising silicon nitride over the first insulating film;   a third insulating film comprising an organic material over the second insulating film;   a light-transmitting conductive layer over the third insulating film, wherein the light-transmitting conductive layer is electrically connected to the transistor;   a liquid crystal layer over the light-transmitting conductive layer;   a counter electrode over the liquid crystal layer,   a second substrate over the first substrate; and   a sealing material between the first substrate and the second substrate, wherein the sealing material is provided to surround the pixel portion,   wherein the sealing material is overlapped with the first insulating film and the second insulating film;   wherein the sealing material is in contact with the second insulating film, and   wherein the sealing material is not overlapped with the third insulating film.   
     
     
         11 . The display device according to  claim 10 , wherein the first insulating film comprises silicon oxide. 
     
     
         12 . The display device according to  claim 10 , wherein the organic material is acrylic. 
     
     
         13 . The display device according to  claim 10 , wherein the light-transmitting conductive layer comprises one of indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium tin oxide, indium zinc oxide, and indium tin oxide to which silicon oxide is added. 
     
     
         14 . A display device comprising:
 a pixel portion comprising a first transistor over a first substrate, the first transistor comprising:
 a first gate electrode; 
 a first gate insulating layer over the first gate electrode; 
 a first oxide semiconductor layer including a channel formation region over the first gate insulating layer, wherein the first oxide semiconductor layer comprises indium, zinc and oxygen; and 
 a first conductive layer in contact with the first oxide semiconductor layer, 
   a protective circuit comprising a second transistor over the first substrate, the second transistor comprising:
 a second gate electrode; 
 a second gate insulating layer over the second gate electrode; 
 a second oxide semiconductor layer including a channel formation region over the second gate insulating layer, wherein the second oxide semiconductor layer comprises indium, zinc and oxygen; and 
 a second conductive layer in contact with the second oxide semiconductor layer, 
   a first insulating film over the first transistor and the second transistor;   a second insulating film comprising silicon nitride over the first insulating film;   a third insulating film comprising an organic material over the second insulating film;   a light-transmitting conductive layer over the third insulating film;   a second substrate over the first substrate; and   a sealing material between the first substrate and the second substrate, wherein the sealing material is provided to surround the pixel portion and the protective circuit,   wherein the sealing material is overlapped with the first insulating film and the second insulating film;   wherein the sealing material is in contact with the second insulating film,   wherein the sealing material is not overlapped with the third insulating film,   wherein the first insulating film, the second insulating film, and the third insulating film are overlapped with the pixel portion and the protective circuit, and   wherein at least one of the second gate electrode and the second conductive layer is electrically connected to a common wiring.   
     
     
         15 . The display device according to  claim 14 , wherein the first insulating film comprises silicon oxide. 
     
     
         16 . The display device according to  claim 14 , wherein the organic material is acrylic. 
     
     
         17 . The display device according to  claim 14 , wherein the light-transmitting conductive layer comprises one of indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium tin oxide, indium zinc oxide, and indium tin oxide to which silicon oxide is added. 
     
     
         18 . The display device according to  claim 14 , further comprising a light-emitting element electrically connected to the first transistor. 
     
     
         19 . The display device according to  claim 14 , wherein the second conductive layer is electrically connected to a scan line through a third conductive layer.