Light-emitting device and electric appliance

A display device comprising:

• a display portion comprising a plurality of pixels formed over a substrate;
• and
• a driver circuit formed over the substrate,
• wherein the driver circuit comprises:
• a shift register containing a plurality of flip-flop circuits comprising enhancement-type n-channel thin film transistors and depletion-type n-channel thin film transistors;
• and
• a plurality of NAND circuits each comprising a first enhancement-type n-channel thin film transistor, a second enhancement-type n-channel thin film transistor, and a depletion-type n-channel thin film transistor,
• wherein a gate electrode of the first enhancement-type n-channel thin film transistor is connected to an output line of one of the plurality of flip-flop circuits,
• wherein a source electrode of the first enhancement-type n-channel thin film transistor is connected to a ground power supply line,
• wherein a drain electrode of the first enhancement-type n-channel thin film transistor is connected to the second enhancement-type n-channel thin film transistor, and
• wherein all semiconductor elements in the display portion and the driver circuit are n-channel type semiconductor elements.

A display device comprising:

• a display portion comprising a plurality of pixels formed over a substrate;
• and
• a driver circuit formed over the substrate,
• wherein the driver circuit comprises:
• a buffer section;
• and
• a shift register containing a plurality of flip-flop circuits comprising enhancement-type n-channel thin film transistors and depletion-type n-channel thin film transistors, and
• wherein all semiconductor elements in the display portion and the driver circuit are n-channel type semiconductor elements.

A display device comprising:

• a display portion comprising a plurality of pixels formed over a substrate;
• and
• a driver circuit formed over the substrate,
• wherein the driver circuit comprises:
• a transfer gate;
• and
• a shift register containing a plurality of flip-flop circuits comprising enhancement-type n-channel thin film transistors and depletion-type n-channel thin film transistors, and
• wherein all semiconductor elements in the display portion and the driver circuit are n-channel type semiconductor elements.

A display device comprising:

• a display portion comprising a plurality of pixels formed over a substrate;
• and
• a driver circuit formed over the substrate,
• wherein the driver circuit comprises:
• a buffer section;
• a transfer gate;
• and
• a shift register containing a plurality of flip-flop circuits comprising enhancement-type n-channel thin film transistors and depletion-type n-channel thin film transistors, and
• wherein all semiconductor elements in the display portion and the driver circuit are n-channel type semiconductor elements.

A display device comprising:

• a display portion comprising a plurality of pixels formed over a substrate;
• and
• a driver circuit formed over the substrate,
• wherein each of the plurality of pixels comprises an enhancement-type n-channel thin film transistor and a depletion-type n-channel thin film transistor, and
• wherein all semiconductor elements in the display portion and the driver circuit are n-channel type semiconductor elements.

A display device comprising:

• a display portion comprising a plurality of pixels formed over a substrate;
• and
• a driver circuit formed over the substrate,
• wherein each of the plurality of pixels comprises an SRAM comprising an enhancement-type n-channel thin film transistor and a depletion-type n-channel thin film transistors, and
• wherein all semiconductor elements in the display portion and the driver circuit are n-channel type semiconductor elements.