ORGANIC ELECTROLUMINESCENT DISPLAY DEVICE AND METHOD OF PRODUCING THE SAME

• US 20090230890A1
• Filed: 03/16/2009
• Published: 09/17/2009
• Est. Priority Date: 03/17/2008
• Status: Abandoned Application

• Current Assignee: UDC Ireland Limited (Universal Display Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Takahara, Kazuhiro
• Application Number:
  US12/404,523
• Publication Number:
  US 20090230890A1
• Time in Patent Office: Days
• US Class Current: 315/307
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/1237 with a different composition, shape, layout or thickness of the gate insulator in different devices
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An organic electroluminescent display device in which a plurality of light-emitting cells each having an organic electroluminescent portion are arranged on a substrate, wherein a plurality of organic electroluminescent portions included in the plurality of light-emitting cells include at least three organic electroluminescent portions which emit different colors, each of the light-emitting cells has a driving transistor which drives the organic electroluminescent portion included in the light-emitting cell, and an amount of an output current of the driving transistor under same driving conditions is different depending on emission color of the organic electroluminescent portion included in the light-emitting cell including the driving transistor.

Claims

1. An organic electroluminescent display device in which a plurality of light-emitting cells each having an organic electroluminescent portion are arranged on a substrate, wherein

a plurality of organic electroluminescent portions included in said plurality of light-emitting cells comprise at least three organic electroluminescent portions which emit different colors,

each of said light-emitting cells has a driving transistor which drives said organic electroluminescent portion included in said light-emitting cell, and

an amount of an output current of said driving transistor under same driving conditions is different depending on emission color of said organic electroluminescent portion included in said light-emitting cell comprising said driving transistor.

2. The organic electroluminescent display device according to claim 1, wherein a difference in amount of the output currents of said driving transistors is obtained from a difference in mobility of said driving transistors.

3. The organic electroluminescent display device according to claim 2, wherein

said plurality of organic electroluminescent portions included in said plurality of light-emitting cells comprise R-color organic electroluminescent portions which emit red light, G-color organic electroluminescent portions which emit green light, and B-color organic electroluminescent portions which emit blue light, and,

in said driving transistors, an R-color mobility indicating mobilities of R-color driving transistors which drive said R-color organic electroluminescent portions, a G-color mobility indicating mobilities of G-color driving transistors which drive said G-color organic electroluminescent portions, and B-color mobility indicating mobilities of B-color driving transistors which drive said B-color organic electroluminescent portions have a relationship of

(R-color mobility)>

(G-color mobility)>

(B-color mobility).

4. The organic electroluminescent display device according to claim 2, wherein a difference in mobility of said driving transistors is obtained from a difference in electron carrier concentration of active layers of said driving transistors.

5. The organic electroluminescent display device according to claim 3, wherein a difference in mobility of said driving transistors is obtained from a difference in electron carrier concentration of active layers of said driving transistors.

6. The organic electroluminescent display device according to claim 1, wherein a difference in amount of the output currents of said driving transistors is obtained from a difference in thickness of gate insulating films of said driving transistors.

7. The organic electroluminescent display device according to claim 2, wherein a difference in amount of the output currents of said driving transistors is obtained from a difference in thickness of gate insulating films of said driving transistors.

8. The organic electroluminescent display device according to claim 3, wherein a difference in amount of the output currents of said driving transistors is obtained from a difference in thickness of gate insulating films of said driving transistors.

9. The organic electroluminescent display device according to claim 6, wherein

said plurality of organic electroluminescent portions included in said plurality of light-emitting cells comprise R-color organic electroluminescent portions which emit red light, G-color organic electroluminescent portions which emit green light, and B-color organic electroluminescent portions which emit blue light, and,

in said driving transistors, an R-color gate insulating film thickness indicating thicknesses of gate insulating films of R-color driving transistors which drive said R-color organic electroluminescent portions, a G-color gate insulating film thickness indicating thicknesses of gate insulating films of G-color driving transistors which drive said G-color organic electroluminescent portions, and a B-color gate insulating film thickness indicating thicknesses of gate insulating films of B-color driving transistors which drive said B-color organic electroluminescent portions have a relationship of

(R-color gate insulating film thickness)<

(G-color gate insulating film thickness)<

(B-color gate insulating film thickness).

10. The organic electroluminescent display device according to claim 7, wherein

said plurality of organic electroluminescent portions included in said plurality of light-emitting cells comprise R-color organic electroluminescent portions which emit red light, G-color organic electroluminescent portions which emit green light, and B-color organic electroluminescent portions which emit blue light, and,

in said driving transistors, an R-color gate insulating film thickness indicating thicknesses of gate insulating films of R-color driving transistors which drive said R-color organic electroluminescent portions, a G-color gate insulating film thickness indicating thicknesses of gate insulating films of G-color driving transistors which drive said G-color organic electroluminescent portions, and a B-color gate insulating film thickness indicating thicknesses of gate insulating films of B-color driving transistors which drive said B-color organic electroluminescent portions have a relationship of

(R-color gate insulating film thickness)<

(G-color gate insulating film thickness)<

(B-color gate insulating film thickness).

11. The organic electroluminescent display device according to claim 8, wherein

said plurality of organic electroluminescent portions included in said plurality of light-emitting cells comprise R-color organic electroluminescent portions which emit red light, G-color organic electroluminescent portions which emit green light, and B-color organic electroluminescent portions which emit blue light, and,

in said driving transistors, an R-color gate insulating film thickness indicating thicknesses of gate insulating films of R-color driving transistors which drive said R-color organic electroluminescent portions, a G-color gate insulating film thickness indicating thicknesses of gate insulating films of G-color driving transistors which drive said G-color organic electroluminescent portions, and a B-color gate insulating film thickness indicating thicknesses of gate insulating films of B-color driving transistors which drive said B-color organic electroluminescent portions have a relationship of

(R-color gate insulating film thickness)<

(G-color gate insulating film thickness)<

(B-color gate insulating film thickness).

12. The organic electroluminescent display device according to claim 1, wherein a difference in amount of the output currents of said driving transistors is obtained from a difference in dielectric constant of gate insulating films of said driving transistors.

13. The organic electroluminescent display device according to claim 12, wherein

said plurality of organic electroluminescent portions included in said plurality of light-emitting cells comprise R-color organic electroluminescent portions which emit red light, G-color organic electroluminescent portions which emit green light, and B-color organic electroluminescent portions which emit blue light, and,

in said driving transistors, an R-color insulating film dielectric constant indicating dielectric constants of gate insulating films of R-color driving transistors which drive said R-color organic electroluminescent portions, a G-color insulating film dielectric constant indicating dielectric constants of gate insulating films of G-color driving transistors which drive said G-color organic electroluminescent portions, and a B-color insulating film dielectric constant indicating dielectric constants of gate insulating films of B-color driving transistors which drive said B-color organic electroluminescent portions have a relationship of

(R-color insulating film dielectric constant)>

(G-color insulating film dielectric constant)>

(B-color insulating film dielectric constant).

14. The organic electroluminescent display device according to claim 1, wherein active layers of said driving transistors are formed by an amorphous oxide semiconductor.

15. The organic electroluminescent display device according to claim 2, wherein active layers of said driving transistors are formed by an amorphous oxide semiconductor.

16. The organic electroluminescent display device according to claim 3, wherein active layers of said driving transistors are formed by an amorphous oxide semiconductor.

17. The organic electroluminescent display device according to claim 4, wherein active layers of said driving transistors are formed by an amorphous oxide semiconductor.

18. The organic electroluminescent display device according to claim 5, wherein active layers of said driving transistors are formed by an amorphous oxide semiconductor.

19. The organic electroluminescent display device according to claim 6, wherein active layers of said driving transistors are formed by an amorphous oxide semiconductor.

20. A method for producing an organic electroluminescent display device in which a plurality of light-emitting cells each having an organic electroluminescent portion are arranged on a substrate, wherein

a plurality of organic electroluminescent portions included in said plurality of light-emitting cells comprise at least three kinds of organic electroluminescent portions which emit different colors,

each of said light-emitting cells has a driving transistor which drives said organic electroluminescent portion included in said light-emitting cell,

said method comprises:

a first step of forming active layers of said driving transistors on said substrate; and

a second step of irradiating said active layers of said driving transistors which drive at least two kinds of organic electroluminescent portions among said at least three kinds of organic electroluminescent portions, respectively, with ultraviolet ray or plasma, and,

in said second step, an amount of irradiation of the ultraviolet ray or plasma on said active layers is different depending on the kinds of said organic electroluminescent portions which are driven by said driving transistors including said active layers.