Display device

The invention provides a method and apparatus to obtain accurate gradation by obtaining an accurate ratio of light emitting parts in a display device which implements gradation by forming a plurality of TFTs and a plurality of OELDs in each pixel, directly connecting the TFTs and OELDs, and switching an on and off state of the TFTs, and controlling a light emitting area of the OELDs. A plurality of OELDs have the same shape, and gradation can be implemented by controlling the number of OELDs that emit light. A plurality of OELDs have a round shape. A plurality of OELDs are arranged at the same interval in a vertical and/or horizontal direction. According to this structure, because the light emitting areas of the plurality of OELDs become equal to each other, by controlling the number of OELDs, a ratio of the light emitting areas can be accurately obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a pixel of conventional TFT-OELD which implements a gradation display by changing a TFT conductance;

FIG. 2 is a cross-sectional view of a conventional TFT-OELD;

FIG. 3 is a diagram showing one pixel of a TFT-OELD which implements a gradation display by changing a conventional OELD light emitting area;

FIG. 4 is a diagram showing a TFT-OELD driving method which implements a gradation display by changing a conventional OELD light emitting area;

FIGS.

5(

a) and

5(

b) are cross-sectional views of an OELD in a TFT-OELD which implements a gradation display by changing a conventional OELD light emitting area (when the side surface of the bank is lyophilic), where FIG.

5(

a) is a diagram of an OELD (lower bit) and FIG.

5(

b) is a diagram of an OELD (upper bit);

FIGS.

6(

a) and

6(

b) are cross-sectional views of an OELD in a TFT-OELD which implements a gradation display by changing a conventional OELD light emitting area (when the side surface of the bank is lyophobic), where FIG.

6(

a) is a diagram of an OELD (lower bit), and FIG.

6(

b) is a diagram of an OELD (upper bit);

FIG. 7 is a diagram showing one pixel of a TFT-OELD related to embodiment 1 of this invention;

FIG. 8 is a diagram showing one pixel of a TFT-OELD related to embodiment 2 of this invention; and

FIG. 9 is a diagram showing one pixel of a TFT-OELD related to embodiment 3 of this invention.

1. A display device comprising a plurality of pixels, each of the plurality of pixels including:

2. The display device according to claim 1, wherein gates of at least two of the plurality of sampling transistors are connected to one scanning line.

3. The display device according to claim 1, wherein the plurality of light emitting elements are organic electroluminescent elements.

4. The display device according to claim 1, wherein the at least one of the plurality of driving transistors are connected to a signal line through a source or drain, and another of the plurality of driving transistors being connected to another signal line through a corresponding source or drain.

5. The display device according to claim 1, wherein the resistance of each of the plurality of driving transistors is determined by binary data.

6. The display device according to claim 1, wherein shapes of the light emitting areas are of no vertex.

7. The display device according to claim 6, wherein the shapes of the light emitting areas are round.