OLED DISPLAY WITH IMPROVED ACTIVE MATRIX CIRCUITRY

• US 20060197458A1
• Filed: 03/01/2005
• Published: 09/07/2006
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Winters, Dustin L., Ludwicki, John E.
• Granted Patent: US 7,190,122 B2
• Time in Patent Office: Days
• US Class Current: 315/169.1
• 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 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]

Abstract

An OLED display for producing a multicolor image includes a plurality of pixels including three different colored addressable gamut-pixels and a fourth addressable within-gamut-pixel, each pixel having a separately addressable organic light-emitting diode with first and second electrodes and one or more organic light emissive layers provided between the electrodes; active matrix circuitry including a separate power transistor for at least two of the three different colored addressable gamut-pixels for regulating current between a first and second voltage source through the organic light-emitting diode of the colored addressable gamut-pixel; and the active matrix circuitry including a power transistor for the fourth addressable within-gamut-pixel for regulating current between a third and fourth voltage source through the organic light-emitting diode of the fourth addressable within-gamut-pixel wherein at least three of the first, second, third, and fourth voltage sources provide different voltage levels.

Claims

1. An OLED display for producing a multicolor image, comprising:

a) a plurality of pixels including three different colored addressable gamut-pixels and a fourth addressable within-gamut-pixel, each pixel having a separately addressable organic light-emitting diode with first and second electrodes and one or more organic light emissive layers provided between the electrodes;

b) active matrix circuitry including a separate power transistor for at least two of the three different colored addressable gamut-pixels for regulating current between a first and second voltage source through the organic light-emitting diode of the colored addressable gamut-pixel; and

c) the active matrix circuitry including a power transistor for the fourth addressable within-gamut-pixel for regulating current between a third and fourth voltage source through the organic light-emitting diode of the fourth addressable within-gamut-pixel wherein at least three of the first, second, third, and fourth voltage sources provide different voltage levels.

2. An OLED display for producing a multicolor image, comprising:

a) a plurality of pixels including three different colored addressable gamut-pixels and a fourth addressable within-gamut-pixel, each pixel having a separately addressable organic light-emitting diode with first and second electrodes and one or more organic light emissive layers provided between the electrodes;

b) active matrix circuitry including a separate power transistor for at least two of the three different colored addressable gamut-pixels for regulating current between a first and second voltage source through the organic light-emitting diode of the colored addressable gamut-pixel;

c) the active matrix circuitry including a power transistor for the fourth addressable within-gamut-pixel for regulating current between a third and fourth voltage source through the organic light-emitting diode of the fourth addressable within-gamut-pixel; and

d) wherein the magnitude of the difference between the voltage levels of the third and fourth voltage sources is less than the magnitude of the difference between the voltage levels of the first and second voltage sources.

3. The OLED display of claim 2 wherein the three different colored addressable gamut-pixels respectively produce red, green, and blue light and the fourth addressable within-gamut-pixel produces white light.

4. The OLED display of claim 2 wherein the active matrix circuitry includes a separate power transistor for the three different colored addressable gamut-pixels for regulating current between the first and second voltage source through the organic light-emitting diode of the colored addressable gamut-pixel.

5. The OLED display of claim 2 wherein the second and fourth voltage sources are the same.

6. The OLED display of claim 2 wherein a power line is associated with the power transistor of each different colored addressable gamut-pixel to provide current from the first voltage source through the power transistor and into the corresponding organic light-emitting diode to the second voltage source.

7. The OLED display of claim 6 wherein the power lines associated with the power transistor of each of the different colored addressable gamut-pixels are connected together.

8. The OLED display of claim 6 wherein the power lines associated with the power transistor of the different colored addressable gamut-pixels are connected together on one side of the display.

9. The OLED display of claim 2 wherein a power line is associated with the power transistor of the fourth addressable within-gamut-pixel to provide current from the third voltage source through the power transistor and into the corresponding organic light-emitting diode to the fourth voltage source.

10. The OLED display of claim 9 further including a plurality of fourth addressable within-gamut-pixels and each of the power lines associated with the plurality of fourth addressable within-gamut-pixels are connected together.

11. The OLED display of claim 9 further including a plurality of fourth addressable within-gamut-pixels and each of the power lines associated with the plurality of fourth addressable within-gamut-pixels are connected together on one side of the display.

12. An OLED display for producing a multicolor image, comprising:

a) a plurality of pixels including three different colored addressable gamut-pixels and a fourth addressable within-gamut-pixel, each pixel having a separately addressable organic light-emitting diode with first and second electrodes and one or more organic light emissive layers provided between the electrodes;

b) active matrix circuitry including a separate power transistor for at least two of the three different colored addressable gamut-pixels for regulating current through the organic light-emitting diode of the colored addressable gamut-pixel wherein the power transistors of the at least two of the three different colored addressable gamut-pixels each have a channel region having a first channel width to channel length ratio; and

c) the active matrix circuitry including a power transistor for the fourth addressable within-gamut-pixel for regulating current through the organic light-emitting diode of the fourth addressable within-gamut-pixel wherein the power transistor of the fourth addressable within-gamut-pixel has a channel region having a second channel width to channel length ratio and wherein the first and second channel width to channel length ratios are different.

13. The OLED display of claim 12 wherein the first channel width to channel length ratio is greater than the second channel width to channel length ratio.

14. The OLED display of claim 12 wherein the active matrix circuitry includes a separate power transistor for all of the three different colored addressable gamut-pixels for regulating current through the organic light-emitting diode of the colored addressable gamut-pixel wherein all of the separate power transistors of the three different colored addressable gamut-pixels each have a channel region having the same channel width to channel length ratio.

15. The OLED display of claim 12 wherein the separate power transistors for at least two of the three different colored addressable gamut-pixels regulate current between a first and second voltage source through the organic light-emitting diode of the colored addressable gamut-pixel and the power transistor for the fourth addressable within-gamut-pixel regulates current between a third and fourth voltage source through the organic light-emitting diode of the fourth addressable within-gamut-pixel and magnitude of the difference between the voltage levels of the third and fourth voltage sources is less than the magnitude of the difference between the voltage levels of the first and second voltage sources.

16. The OLED display of claim 15 wherein the second and fourth voltage sources are the same.

17. The OLED display of claim 12 wherein the three different colored addressable gamut-pixels respectively produce red, green, and blue light and the fourth addressable within-gamut-pixel produces white light.