US 2009/0021287 A1Published application

Circuit and method for driving organic light emitting diode

AssigneeJin Jang

InventorsJin Jang, Joon-Chul Goh

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Abstract

A drive circuit for organic light emitting diodes (OLEDs), and a method for driving OLEDs, using the drive circuit. The drive circuit includes pixel circuits, each of which includes a first transistor for receiving a data voltage, and outputting a drive current to an OLED, a second transistor for transmitting the data voltage to the first transistor, a third transistor for connecting the gate and drain of the first transistor, a capacitor for storing a gate voltage of the first transistor, and a fourth transistor connected to the drain of the first transistor. The OLED is connected to the source of the first transistor by a fifth transistor, or is directly connected to the source of the first transistor without using the fifth transistor. The drive circuit generates drive current, based on a non-uniformity-compensated threshold voltage of the first transistor, thereby obtaining a uniform luminance of the OLED.

Claims18

Dependent claims

A drive circuit for organic light emitting diodes comprising a scanning line drive circuit for sequentially applying a select or nonselect signal to scanning lines, a data line drive circuit for applying, to data lines, voltages corresponding to respective pieces of image information associated with the data lines, and pixel circuits arranged at intersections between the scanning lines and the data lines, wherein each of the pixel circuits comprises:

an organic light emitting diode (OLED) having two terminals;
a first transistor having a gate, a source, and a drain, the first transistor supplying a current to the OLED in accordance with a voltage applied to the first transistor;
a second transistor having a gate, a source, and a drain, where the gate of the second transistor is connected to a first scanning line, where the source of the second transistor is connected to a data line, where the drain of the second transistor is connected to the source of the first transistor;
a third transistor having a gate, a source, and a drain, where the gate of the third transistor is connected to a second scanning line, where the source of the third transistor is connected to the gate of the first transistor, where the drain of the third transistor is connected to the drain of the first transistor;
a fourth transistor having a gate, a source, and a drain, where the gate of the fourth transistor is connected to a third scanning line, where the source of the fourth transistor is connected to a power line, where the drain of the fourth transistor is connected to the drain of the first transistor;
a fifth transistor having a gate, a source, and a drain, where the gate of the fifth transistor is connected to a fourth scanning line, where the source of the fifth transistor is connected to the source of the first transistor, where the drain of the fifth transistor is connected to one of the terminals of the OLED;
and
a capacitor having two terminals, where one of the terminals of the capacitor is connected to the gate of the first transistor.

5 more elements

A drive circuit for organic light emitting diodes comprising a scanning line drive circuit for sequentially applying a select or non-select signal to scanning lines, a data line drive circuit for applying, to data lines, voltages corresponding to respective pieces of image information associated with the data lines, and pixel circuits arranged at intersections between the scanning lines and the data lines, wherein each of the pixel circuits comprises:

a first transistor having a gate, a source, and a drain, the first transistor supplying a current to an organic light emitting diode (OLED) in accordance with a voltage applied to the first transistor;
a second transistor having a gate, a source, and a drain, where the gate of the second transistor is connected to a first scanning line, where the source of the second transistor is connected to a data line, where the drain of the second transistor is connected to the source of the first transistor;
a third transistor having a gate, a source, and a drain, where the gate of the third transistor is connected to a second scanning line, where the source of the third transistor is connected to the gate of the first transistor, where the drain of the third transistor is connected to the drain of the first transistor;
a fourth transistor having a gate, a source, and a drain, where the gate of the fourth transistor is connected to a third scanning line, where the source of the fourth transistor is connected to a power line, where the drain of the fourth transistor is connected to the drain of the first transistor;
a capacitor having two terminals, where one of the terminals of the capacitor is connected to the gate of the first transistor;
and
the OLED, which has two terminals, where one of the terminals of the OLED is connected to the source of the first transistor, where the other terminal of the OLED is connected to a fourth scanning line.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/662,605Filed 15 Sep 2004
Published: 22 Jan 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G09G 3/3233
Using an active matrix: with pixel circuitry controlling the current through the light-emitting element
G09G 3/3291
Details of drivers for data electrodes: in which the data driver supplies a variable data voltage for setting the current through, or the voltage…
G09G 2300/0819
Several active elements per pixel in active matrix panels: used for counteracting undesired variations, e.g. feedback or autozeroing
G09G 2300/0842
Several active elements per pixel in active matrix panels: forming a memory circuit, e.g. a dynamic memory with one capacitor