US 2006/0125737 A1Published application

Pixel and light emitting display

AssigneeSamsung Mobile Display Co., Ltd.

InventorsWon Kwak, Sung Park

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Abstract

A pixel and a light emitting display including the pixel. The pixel includes first and second organic light emitting diodes (OLEDs), a driving circuit commonly connected to the plurality of OLEDs to drive the first and second OLEDs, a switching circuit connected between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs using first and second emission control signals, and a reverse bias circuit for selectively applying a reverse bias voltage including at least one of the first and second emission control signals to the first and second OLEDs. Therefore, the reverse bias can be easily applied in the periods when the OLEDs do not emit light and thus can improve the characteristics of the OLEDs. Also, since, the first and second OLEDs are connected to one pixel circuit, it is possible to reduce the number of pixels of the light emitting display and thus to improve the aperture ratio of the light emitting display.

Claims25

Dependent claims

A pixel comprising:

first and second organic light emitting diodes (OLEDs);
a driving circuit commonly connected to the first and second OLEDs to drive the first and second OLEDs;
a switching circuit connected between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs using first and second emission control signals;
and
a reverse bias circuit for selectively applying a reverse bias voltage comprising at least one of the first and second emission control signals to the first and second OLEDs,
wherein the driving circuit comprises:
a first transistor for receiving a first power of a first power source to selectively supply a driving current corresponding to a first voltage applied to a gate at the first transistor to the first and second OLEDs;
a second transistor for selectively applying a data signal to a first electrode of the first transistor in accordance with a first scan signal;
a third transistor for selectively connecting the first transistor to serve as a diode in accordance with the first scan signal so that an electric current can flow through the first transistor;
a capacitor for storing the voltage applied to the gate of the first transistor while the data signal is applied to the first electrode of the first transistor and for maintaining the stored voltage at the gate of the first transistor for a period when at least one of the first and second OLEDs emits light;
a fourth transistor for selectively applying an initializing voltage to the capacitor in accordance with a second scan signal;
a fifth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the first emission control signal;
and
a sixth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the second emission control signal.

11 more elements

A pixel comprising:

first and second organic light emitting diodes (OLEDs);
a driving circuit commonly connected to the first and second OLEDs to drive the first and second OLEDs;
a switching circuit connected between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs using first and second emission control signals;
and
a reverse bias circuit connected to a reverse bias line for transmitting a reverse bias voltage to selectively apply the reverse bias voltage to the first and second OLEDs in accordance with the first and second emission control signals so that the reverse bias voltage is applied to the first and second OLEDs,
wherein the driving circuit comprises:
a first transistor for receiving a first power of a first power source to selectively supply a driving current corresponding to a first voltage applied to a gate of the first transistor to the first and second OLEDs;
a second transistor for selectively applying a data signal to a first electrode of the first transistor in accordance with a first scan signal;
a third transistor for selectively connecting the first transistor to serve as a diode in accordance with the first scan signal so that an electric current can flow through the first transistor;
a capacitor for storing the voltage applied to the gate of the first transistor while the data signal is applied to the first electrode of the first transistor and for maintaining the stored voltage at the gate of the first transistor for a period when at least one of the first and second OLEDs emits light;
a fourth transistor for selectively applying an initializing voltage to the capacitor in accordance with a second scan signal;
a fifth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the first emission control signal;
and
a sixth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the second emission control signal.

11 more elements

A pixel comprising:

first and second organic light emitting diodes (OLEDs);
a driving circuit commonly connected to the first and second OLEDs to drive the first and second OLEDs;
a switching circuit connected between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs using first and second emission control signals;
and
a reverse bias circuit connected to a reverse bias line for transmitting a reverse bias voltage and a reverse bias control line for transmitting a reverse voltage control signal to selectively apply the reverse bias voltage to the first and second OLEDs in accordance with the reverse voltage control signal so that the reverse bias voltage is applied to the first and second OLEDs,
wherein the driving circuit comprises:
a first transistor for receiving a first power of a first power source to selectively supply a driving current corresponding to a first voltage applied to a gate of the first transistor to the first and second OLEDs;
a second transistor for selectively applying a data signal to a first electrode of the first transistor in accordance with a first scan signal;
a third transistor for selectively connecting the first transistor to serve as a diode in accordance with the first scan signal so that an electric current can flow through the first transistor;
a capacitor for storing the voltage applied to the gate of the first transistor while the data signal is applied to the first electrode of the first transistor and for maintaining the stored voltage at the gate of the first transistor for a period when at least one of the first and second OLEDs emits light;
a fourth transistor for selectively applying an initializing voltage to the capacitor in accordance with a second scan signal;
a fifth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the first emission control signal;
and
a sixth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the second emission control signal.

11 more elements

A light emitting display comprising:

an image display unit including a plurality of pixels to display an image;
a scan driver for transmitting first and second scan signals and first and second emission control signals to the image display unit;
and
a data driver for transmitting a data signal to the image display unit,
wherein at least one of the pixels comprises:
first and second organic light emitting diodes (OLEDs);
a driving circuit commonly connected to the first and second OLEDs to drive the first and second OLEDs;
a switching circuit connected between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs using the first and second emission control signals;
and
a reverse bias circuit for selectively applying a reverse bias voltage comprising at least one of the first and second emission control signals to the first and second OLEDs,
wherein the driving circuit comprises:
a first transistor for receiving a first power of a first power source to selectively supply a driving current corresponding to a first voltage applied to a gate of the first transistor to the first and second OLEDs;
a second transistor for selectively applying a data signal to a first electrode of the first transistor in accordance with the first scan signal;
a third transistor for selectively connecting the first transistor to serve as a diode in accordance with the first scan signal so that an electric current can flow through the first transistor;
a capacitor for storing the voltage applied to the gate of the first transistor while the data signal is applied to the first electrode of the first transistor and for maintaining the stored voltage at the gate of the first transistor for a period when at least one of the first and second OLEDs emits light;
a fourth transistor for selectively applying an initializing voltage to the capacitor in accordance with the second scan signal;
a fifth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the first emission control signal;
and
a sixth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the second emission control signal.

16 more elements

A light emitting display comprising:

an image display unit including a plurality of pixels to display an image;
a scan driver for transmitting first and second scan signals and first and second emission control signals to the image display unit;
and
a data driver for transmitting a data signal to the image display unit,
wherein at least one of the pixels comprises:
first and second organic light emitting diodes (OLEDs);
a driving circuit commonly connected to the first and second OLEDs to drive the first and second OLEDs;
a switching circuit connected between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs using the first and second emission control signals;
and
a reverse bias circuit connected to a reverse bias line for transmitting a reverse bias voltage to selectively apply the reverse bias voltage to the first and second OLEDs in accordance with the first and second emission control signals so that the reverse bias voltage is applied to the first and second OLEDS,
wherein the driving circuit comprises:
a first transistor for receiving a first power of a first power source to selectively supply a driving current corresponding to a first voltage applied to a gate of the first transistor to the first and second OLEDs;
a second transistor for selectively applying a data signal to a first electrode of the first transistor in accordance with the first scan signal;
a third transistor for selectively connecting the first transistor to serve as a diode in accordance with the first scan signal so that an electric current can flow through the first transistor;
a capacitor for storing the voltage applied to the gate of the first transistor while the data signal is applied to the first electrode of the first transistor and for maintaining the stored voltage at the gate of the first transistor for a period when at least one of the first and second OLEDs emits light;
a fourth transistor for selectively applying an initializing voltage to the capacitor in accordance with the second scan signal;
a fifth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the first emission control signal;
and
a sixth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the second emission control signal

16 more elements

A light emitting display comprising:

an image display unit including a plurality of pixels to display an image;
a scan driver for transmitting first and second scan signals and first and second emission control signals to the image display unit;
and
a data driver for transmitting a data signal to the image display unit,
wherein at least one of the pixels comprises:
first and second organic light emitting diodes (OLEDs);
a driving circuit commonly connected to the first and second OLEDs to drive the first and second OLEDs;
a switching circuit connected between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs using the first and second emission control signals;
and
a reverse bias circuit connected to a reverse bias line for transmitting a reverse bias voltage and a reverse bias control line for transmitting a reverse bias voltage control signal to selectively apply the reverse bias voltage to the first and second OLEDs in accordance with the reverse bias voltage control signal so that the reverse bias voltage is applied to the first and second OLEDs,
wherein the driving circuit comprises:
a first transistor for receiving a first power of a first power source to selectively supply a driving current corresponding to a first voltage applied to a gate of the first transistor to the first and second OLEDs;
a second transistor for selectively applying the data signal to a first electrode of the first transistor in accordance with the first scan signal;
a third transistor for selectively connecting the first transistor to serve as a diode in accordance with the first scan signal so that an electric current can flow through the first transistor;
a capacitor for storing the voltage applied to the gate of the first transistor while the data signal is applied to the first electrode of the first transistor and for maintaining the stored voltage at the gate of the first transistor for a period when at least one of the first and second OLEDs emits light;
a fourth transistor for selectively applying an initializing voltage to the capacitor in accordance with the second scan signal;
a fifth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the first emission control signal;
and
a sixth transistor for selectively applying the first power of the first power source to the first transistor in accordance with the second emission control signal.

16 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/274,042Filed 14 Nov 2005
Priority: KR 10-2004-009598322 Nov 2004
Published: 15 Jun 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G09G 3/3233
Using an active matrix: with pixel circuitry controlling the current through the light-emitting element
G09G 2300/0804
Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light…:…
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