Luminescent display device

Abstract

A luminescent display device includes a substrate and a thin-film transistor above the substrate. The thin-film transistor includes a semiconductor layer, a gate insulating film on the semiconductor layer, a gate electrode on the gate insulating film, a source electrode, and a drain electrode. The luminescent display device further includes an interlayer insulating film on the gate electrode, a first capacitor electrode on the interlayer insulating film in a region above the gate electrode, and a luminescent element configured to be driven by a driver to produce luminescence. The driver includes the thin-film transistor, and the first capacitor electrode and the gate electrode constitute a capacitor.

What is claimed is: 
     
       1. A luminescent display device, comprising:
 a substrate; and 
 a plurality of pixels above the substrate, 
 each of the pixels including:
 a thin film transistor above the substrate, the thin film transistor including:
 a semiconductor layer comprising a channel region, a source region, and a drain region; 
 a source electrode electrically connected to the source region of the semiconductor layer; and 
 a drain electrode electrically connected to the drain region of the semiconductor layer; 
 
 a lower electrode above the substrate, the lower electrode including a first portion and a second portion, the first portion of the lower electrode being provided in a region in which the thin film transistor is provided, the first portion of the lower electrode comprising a gate electrode of the thin film transistor, the second portion of the lower electrode being provided in a region other than the region in which the thin-film transistor is provided the lower electrode, including the first portion and the second portion, comprising one continuous layer; 
 an interlayer insulating film on the lower electrode; 
 an upper electrode on the interlayer insulating film, the upper electrode including a first portion and a second portion, the upper electrode, including the first portion and the second portion, comprising one continuous layer, the first portion of the upper electrode comprising a capacitor electrode directly above the gate electrode, the first portion of the upper electrode further comprising the source electrode, the capacitor electrode and the source electrode being connected via a through-hole in the interlayer insulating film; and 
 a luminescent element configured to be driven by a driver to produce luminescence, the driver including the thin film transistor, 
 
 wherein the first portion of the upper electrode and the first portion of the lower electrode comprise a first capacitance, and the second portion of the upper electrode and the second portion of the lower electrode comprise a second capacitance, and 
 the capacitor electrode extends from the second portion of the upper electrode to be directly above the gate electrode, with the upper electrode including a physical separation that overlaps the semiconductor layer and that is between the capacitor electrode and the source electrode. 
 
     
     
       2. The luminescent display device according to  claim 1 ,
 wherein an area of a lower surface of the first portion of the upper electrode, in the region in which the thin film transistor is provided, is approximately 30% to approximately 100% of an area of an upper surface of the gate electrode. 
 
     
     
       3. The luminescent display device according to  claim 1 , wherein the semiconductor layer comprises polysilicon. 
     
     
       4. The luminescent display device according to  claim 1 ,
 wherein the first capacitance is approximately 0.1 pF to approximately 10 pF. 
 
     
     
       5. The luminescent display device according to  claim 1 ,
 wherein the luminescent display device is a top-emission luminescent display device, and 
 the luminescent element is in a layer above the upper electrode. 
 
     
     
       6. The luminescent display device according to  claim 1 ,
 wherein the luminescent display device is a bottom-emission luminescent display device, and 
 the thin-film transistor, the lower electrode, and the upper electrode are in a region other than a luminescent region in which the luminescent element is disposed. 
 
     
     
       7. The luminescent display device according to  claim 1 ,
 wherein the one continuous layer of the upper electrode includes the source electrode of the thin film transistor. 
 
     
     
       8. The luminescent display device according to  claim 7 , further comprising:
 a power line connected to the one of the source electrode and the drain electrode of the thin film transistor, 
 wherein the one continuous layer of the upper electrode further includes the power line. 
 
     
     
       9. A luminescent display device, comprising:
 a substrate; and   a plurality of pixels above the substrate,   each of the pixels including:
 a thin film transistor above the substrate, the thin film transistor including:
 a semiconductor layer comprising a channel region, a source region, and a drain region; 
 a source electrode configured to be electrically connected to the source region of the semiconductor layer; and 
 a drain electrode configured to be electrically connected to the drain region of the semiconductor layer; 
 
 a lower electrode above the substrate, the lower electrode including a first portion and a second portion, the first portion of the lower electrode being provided in a region in which the thin film transistor is provided, the first portion of the lower electrode comprising a gate electrode of the thin film transistor, the second portion of the lower electrode being provided in a region other than the region in which the thin-film transistor is provided, the lower electrode, including the first portion and the second portion, comprising one continuous layer; 
 an interlayer insulating film above the lower electrode; 
 an upper electrode, contacting the interlayer insulating film, which is configured to be electrically connected to one of the source region and the drain region of the semiconductor layer via a through-hole in the interlayer insulating film, the upper electrode including a first portion and a second portion, the upper electrode, including the first portion and the second portion, comprising one continuous layer, the first portion of the upper electrode overlapping the first portion of the lower electrode to form a first capacitance, the second portion of the upper electrode overlapping the second portion of the lower electrode to form a second capacitance; and 
 a luminescent element configured to be driven by a driver to produce luminescence, the driver including the thin film transistor, 
   wherein the first portion of the upper electrode extends from the second portion of the upper electrode to overlap the first portion of the lower electrode to form the first capacitance, with the upper electrode including a physical separation that overlaps the semiconductor layer and that is between the first portion of the upper electrode and a portion of the upper electrode that is configured to be electrically connected to the one of the source region or the drain region.   
     
     
       10. The luminescent display device according to claim 9, wherein an area of a lower surface of the first portion of the upper electrode, in the region in which the thin film transistor is provided, is approximately 30% to approximately 100% of an area of an upper surface of the gate electrode. 
     
     
       11. The luminescent display device according to claim 9, wherein the semiconductor layer comprises polysilicon. 
     
     
       12. The luminescent display device according to claim 9, wherein the first capacitance is approximately 0.1 pF to approximately 10 pF. 
     
     
       13. The luminescent display device according to claim 9, wherein the luminescent display device is a top-emission luminescent display device, and the luminescent element is in a layer above the upper electrode. 
     
     
       14. The luminescent display device according to claim 9, wherein a part of the upper electrode constitutes one of the source electrode and the drain electrode. 
     
     
       15. The luminescent display device according to claim 14, wherein the first portion of the upper electrode, the second portion of the upper electrode, and the part of the upper electrode which constitutes the one of the source electrode and the drain electrode comprise one continuous layer. 
     
     
       16. The luminescent display device according to claim 15, wherein the first portion of the upper electrode is connected to the one of the source electrode and the drain electrode via the through-hole in the interlayer insulating film. 
     
     
       17. The luminescent display device according to claim 9, wherein the first portion of the upper electrode is configured to be electrically connected to one of the source electrode and the drain electrode. 
     
     
       18. The luminescent display device according to claim 17, wherein the first portion of the upper electrode, the second portion of the upper electrode, and the one of the source electrode and the drain electrode comprise one continuous layer. 
     
     
       19. The luminescent display device according to claim 18, wherein the first portion of the upper electrode is connected to the source electrode via the through-hole in the interlayer insulating film. 
     
     
       20. The luminescent display device according to claim 9, wherein the first portion of the upper electrode, the second portion of the upper electrode, and one of the source electrode and the drain electrode comprise one continuous layer. 
     
     
       21. A luminescent display device, comprising:
 a substrate; and   a plurality of pixels above the substrate,   each of the pixels including:
 a driving transistor above the substrate; 
 a semiconductor layer comprising a channel region, a source region, and a drain region; 
 a source electrode configured to be electrically connected to the source region of the semiconductor layer; 
 a drain electrode configured to be electrically connected to the drain region of the semiconductor layer; 
 a lower electrode above the substrate, the lower electrode including a first portion and a second portion, the first portion of the lower electrode being provided in a region in which the driving transistor is provided, the first portion of the lower electrode comprising a gate electrode of the driving transistor, the second portion of the lower electrode being provided in a region other than the region in which the driving transistor is provided, the lower electrode, including the first portion and the second portion, comprising one continuous layer; 
 an interlayer insulating film above the lower electrode; 
 an upper electrode, contacting the interlayer insulating film, which is configured to be electrically connected to one of the source region and the drain region of the semiconductor layer via a through-hole in the interlayer insulating film, the upper electrode including a first portion and a second portion, the upper electrode, including the first portion and the second portion, comprising one continuous layer, the first portion of the upper electrode overlapping the first portion of the lower electrode to form a first capacitance, the second portion of the upper electrode overlapping the second portion of the lower electrode to form a second capacitance; and 
 a luminescent element configured to be driven by a driver to produce luminescence, the driver including the driving transistor, 
   wherein the first portion of the upper electrode extends from the second portion of the upper electrode to overlap the first portion of the lower electrode to form the first capacitance, with the upper electrode including a physical separation that overlaps the semiconductor layer and that is between the first portion of the upper electrode and a portion of the upper electrode that is configured to be electrically connected to the one of the source region or the drain region.   
     
     
       22. A luminescent display device, comprising:
 a substrate; and   a plurality of pixels above the substrate,   each of the pixels including:
 a thin film transistor above the substrate, the thin film transistor including:
 a semiconductor layer comprising a channel region, a source region, and a drain region; 
 a source electrode configured to be electrically connected to the source region of the semiconductor layer; and 
 a drain electrode configured to be electrically connected to the drain region of the semiconductor layer; 
 
 a lower electrode above the substrate, the lower electrode including a first portion and a second portion, the first portion of the lower electrode being provided in a region in which the thin film transistor is provided, the first portion of the lower electrode comprising a gate electrode of the thin film transistor, the second portion of the lower electrode being provided in a region other than the region in which the thin-film transistor is provided, the lower electrode, including the first portion and the second portion, comprising one continuous layer; 
 an interlayer insulating film above the lower electrode; 
 an upper electrode contacting the interlayer insulating film, the upper electrode including a first portion and a second portion, the upper electrode, including the first portion and the second portion, comprising one continuous layer, the first portion of the upper electrode being above the gate electrode, a part of the upper electrode being connected to the source electrode, the part of the upper electrode and the source electrode being connected via a through-hole in the interlayer insulating film; and 
 a luminescent element configured to be driven by a driver to produce luminescence, the driver including the thin film transistor, 
   wherein the first portion of the upper electrode and the first portion of the lower electrode form a first capacitance in a region corresponding to the channel region,   the second portion of the upper electrode and the second portion of the lower electrode form a second capacitance in a region other than the region corresponding to the channel region, and   the first portion of the upper electrode extends from the second portion of the upper electrode to be above the gate electrode, with the upper electrode including a physical separation that is above the semiconductor layer and that is between the first portion of the upper electrode and the part of the upper electrode that is connected to the source electrode.   
     
     
       23. The luminescent display device according to claim 22, wherein an area of a lower surface of the first portion of the upper electrode, which is above the gate electrode, is approximately 30% to approximately 100% of an area of an upper surface of the gate electrode. 
     
     
       24. The luminescent display device according to claim 22, wherein the semiconductor layer comprises polysilicon. 
     
     
       25. The luminescent display device according to claim 22, wherein the first capacitance is approximately 0.1 pF to approximately 10 pF. 
     
     
       26. The luminescent display device according to claim 22, wherein the luminescent display device is a top-emission luminescent display device, and the luminescent element is in a layer above the upper electrode. 
     
     
       27. The luminescent display device according to claim 22, wherein the first portion of the upper electrode, the second portion of the upper electrode, and the source electrode comprise one continuous layer. 
     
     
       28. A luminescent display device, comprising:
 a substrate; and   a plurality of pixels above the substrate,   each of the pixels including:
 a driving transistor above the substrate; 
 a semiconductor layer comprising a channel region, a source region, and a drain region; 
 a source electrode configured to be electrically connected to the source region of the semiconductor layer; 
 a drain electrode configured to be electrically connected to the drain region of the semiconductor layer; 
 a lower electrode above the substrate, the lower electrode including a first portion and a second portion, the first portion of the lower electrode being provided in a region in which the driving transistor is provided, the first portion of the lower electrode comprising a gate electrode of the driving transistor, the second portion of the lower electrode being provided in a region other than the region in which the driving transistor is provided, the lower electrode, including the first portion and the second portion, comprising one continuous layer; 
 an interlayer insulating film above the lower electrode; 
 an upper electrode contacting the interlayer insulating film, the upper electrode including a first portion and a second portion, the upper electrode, including the first portion and the second portion, comprising one continuous layer, the first portion of the upper electrode being above the gate electrode, a part of the upper electrode being connected to the source electrode, the part of the upper electrode and the source electrode being connected via a through-hole in the interlayer insulating film; and 
 a luminescent element configured to be driven by a driver to produce luminescence, the driver including the driving transistor, 
   wherein the first portion of the upper electrode and the first portion of the lower electrode form a first capacitance in a region corresponding to the channel region,   the second portion of the upper electrode and the second portion of the lower electrode form a second capacitance in a region other than the region corresponding to the channel region, and   the first portion of the upper electrode extends from the second portion of the upper electrode to be above the gate electrode to form the first capacitance, with the upper electrode including a physical separation that is above the semiconductor layer and that is between the first portion of the upper electrode and the part of the upper electrode that is connected to the source electrode.