IP Library Granted Patent US 8,068,074
Granted Patent B2
US 8,068,074 · App. 12/241,360 · Granted Nov 29, 2011

Pixel drive circuit for electroluminescent element

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Quick Facts
Patent No.
US 8,068,074
App. No.
12/241,360
Granted
Nov 29, 2011
Kind
B2
Abstract

A pixel circuit including a storage capacitor to which data is written including a black level; a second driving transistor supplies a drive current corresponding to data written to the storage capacitor to a second organic electroluminescence element; a first driving transistor supplies to a first organic electroluminescence element drive current that reflects brightness degradation or current degradation in the second organic electroluminescence element, wherein the second driving transistor supplies a predetermined drive current to the second organic electroluminescence element including data of the black level; and the drive voltage of the first driving transistor is set to a voltage reflecting the brightness degradation or current degradation in the second organic electroluminescence element.

Claims (29)

1. A pixel circuit comprising:

a first organic electroluminescence element which contributes to light emission;

a second organic electroluminescence element which does not contribute to light emission; a storage capacitor to which data is written including a black level;

a second driving transistor which supplies a drive current corresponding to data written to the storage capacitor to the second organic electroluminescence element;

a first driving transistor which supplies, to the first organic electroluminescence element drive current which corresponds to a drive voltage that reflects brightness degradation or current degradation in the second organic electroluminescence element, the second driving transistor supplying a predetermined drive current to the second organic electroluminescence element including data of the black level; and

means for setting the drive voltage of the first driving transistor to a voltage reflecting the brightness degradation or current degradation in the second organic electroluminescence element,

wherein:

a drive voltage which corresponds to data written to the storage capacitor is supplied to a gate of the second driving transistor, and

the voltage at the intermediate point between the second driving transistor and the second organic electroluminescence element is supplied to a gate of the first driving transistor, and

wherein:

one terminal of the storage capacitor is connected to a power supply line and the other terminal of the storage capacitor is connected to the gate of the second driving transistor,

a source of the first driving transistor and a source of the second driving transistor are connected to the power supply line,

a drain of the first driving transistor is connected to the first organic electroluminescence element, and

a drain of the second driving transistor is connected to the second organic electroluminescence element.

2. A pixel circuit comprising:

a first organic electroluminescence element which contributes to light emission;

a second organic electroluminescence element which does not contribute to light emission; a storage capacitor to which data is written including a black level;

a second driving transistor which supplies a drive current corresponding to data written to the storage capacitor to the second organic electroluminescence element;

a first driving transistor which supplies, to the first organic electroluminescence element drive current which corresponds to a drive voltage that reflects brightness degradation or current degradation in the second organic electroluminescence element, the second driving transistor supplying a predetermined drive current to the second organic electroluminescence element including data of the black level; and

means for setting the drive voltage of the first driving transistor to a voltage reflecting the brightness degradation or current degradation in the second organic electroluminescence element,

wherein:

a drive voltage which corresponds to data written to the storage capacitor is supplied to a gate of the second driving transistor, and

the voltage at the intermediate point between the second driving transistor and the second organic electroluminescence element is supplied to a gate of the first driving transistor, and

wherein:

one terminal of the storage capacitor is connected to a second power supply line and the other terminal of the storage capacitor is connected to the gate of the second driving transistor,

a source of the first driving transistor is connected to a first power supply line,

a source of the second driving transistor is connected to the second power supply line,

a drain of the first driving transistor is connected to the first organic electroluminescence element, and

a drain of the second driving transistor is connected to the second organic electroluminescence element.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 11, 2010
From: EASTMAN KODAK COMPANY
To: GLOBAL OLED TECHNOLOGY LLC
Reel/Frame 024068/0468 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 30, 2008
From: KAWABE, KAZUYOSHI
To: EASTMAN KODAK COMPANY
Reel/Frame 021606/0964 →