EL display device and electronic apparatus
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsKazutaka Inukai, Jun Koyama
Life of this patent
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Abstract
An EL display device capable of clear, multi-gradation color display, and an electronic device having the EL display device, are provided. Gradation display is performed in accordance with a time division driver method which controls by the amount of time an EL element formed in a pixel emits light, and the amount of time it does not emit light. Influence due to dispersion in the characteristics of electric current TFTs is prevented.
Claims8
An EL display device having a pixel portion over a substrate, said pixel portion comprising:
- a switching TFT having a LDD region not overlapping a gate electrode with a gate insulating film interposed therebetween;
- and
- a current control TFT having the LDD region overlapping the gate electrode with the gate insulating film interposed therebetween.
An EL display device having a pixel portion, a source driver circuit and a gate driver circuit over a substrate, said pixel portion comprising:
- a switching TFT having a LDD region not overlapping a gate electrode with a gate insulating film interposed therebetween;
- and
- a current control TFT having the LDD region overlapping the gate electrode with the gate insulating film interposed therebetween.
An EL display device having a pixel portion over a substrate, said pixel portion comprising:
- a switching TFT having a LDD region not overlapping a gate electrode with a gate insulating film interposed therebetween;
- and
- a current control TFT having the LDD region overlapping the gate electrode with the gate insulating film interposed therebetween,
- wherein said switching TFT comprises any one of a p-channel TFT and a n-channel TFT,
- wherein said current control TFT comprises the p-channel TFT, and
- wherein a drain region of said current control TFT is electrically connected to an anode of an EL element.
An EL display device having a pixel portion, a source driver circuit and a gate driver circuit over a substrate, said pixel portion comprising:
- a switching TFT having a LDD region not overlapping a gate electrode with a gate insulating film interposed therebetween;
- and
- a current control TFT having the LDD region overlapping the gate electrode with the gate insulating film interposed therebetween,
- wherein said switching TFT comprises any one of a p-channel TFT and a n-channel TFT,
- wherein said current control TFT comprises the p-channel TFT, and
- wherein a drain region of said current control TFT is electrically connected to an anode of an EL element.
An EL display device having a pixel portion over a substrate, said pixel portion comprising:
- a switching TFT having a LDD region not overlapping a gate electrode with a gate insulating film interposed therebetween;
- and
- a current control TFT having the LDD region overlapping the gate electrode with the gate insulating film interposed therebetween,
- wherein said switching TFT comprises any one of a p-channel TFT and a n-channel TFT,
- wherein said current control TFT comprises the p-channel TFT, and
- wherein a drain region of said current control TFT is electrically connected to a cathode of an EL element.
An EL display device having a pixel portion, a source driver circuit and a gate driver circuit over a substrate, said pixel portion comprising:
- a switching TFT having a LDD region not overlapping a gate electrode with a gate insulating film interposed therebetween;
- and
- a current control TFT having the LDD region overlapping the gate electrode with the gate insulating film interposed therebetween,
- wherein said switching TFT comprises any one of a p-channel TFT and a n-channel TFT,
- wherein said current control TFT comprises the p-channel TFT, and
- wherein a drain region of said current control TFT is electrically connected to a cathode of an EL element.
Dependencies are inferred from the claim text.