US 12,743,996 B2Granted

Pixel circuit and display device having the same

AssigneeSamsung Display Co., Ltd.

InventorsKyoungju Shin, Dohyun Kang, Yangsoo Kim, Jungkook Park, Moonsang Hwang

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Abstract

A pixel circuit includes a light emitting element, a driving transistor, a first emission transistor applying a first power voltage to the driving transistor in response to a first emission signal, a second emission transistor applying the driving current to the light emitting element in response to a second emission signal, a first initialization transistor applying a first initialization voltage to an anode electrode of the light emitting element in response to the second emission signal, a data write transistor, a compensation transistor, a second initialization transistor, and a storage capacitor. A first off-duty ratio which is a ratio of a high voltage level period of the first emission signal in one frame is determined according to a set luminance level, and a second off-duty ratio which is a ratio of a high voltage level period of the second emission signal in the one frame is fixed.

Claims20

Dependent claims

A pixel comprising:

a light emitting element;
a driving transistor generating a driving current;
a first emission transistor connected between a first power voltage line and the driving transistor, and applying a first power voltage to the driving transistor in response to a first emission signal;
a second emission transistor connected between the driving transistor and the light emitting element, and applying the driving current to the light emitting element in response to a second emission signal;
a first initialization transistor applying a first initialization voltage to an anode electrode of the light emitting element in response to the second emission signal;
a data write transistor applying a data voltage to the driving transistor in response to a write gate signal;
a compensation transistor connecting a first electrode of the driving transistor and a control electrode of the driving transistor in response to a compensation gate signal;
a second initialization transistor applying a second initialization voltage to the control electrode of the driving transistor in response to an initialization gate signal;
and
a storage capacitor including a first electrode connected to the control electrode of the driving transistor and a second electrode receiving the first power voltage,
wherein the first emission signal has a first on time in one frame which is determined according to a set luminance level, the first on time corresponding to the set luminance level being stored in a look up table, and
wherein the second emission signal has a second on time in the one frame which is fixed regardless of the set luminance level.

9 more elements

A display device comprising:

a display panel including a pixel;
a data driver applying a data voltage to the pixel;
a gate driver applying a write gate signal, a compensation gate signal, and an initialization gate signal;
an emission driver applying a first emission signal and a second emission signal;
and
a driving controller controlling the display panel, the data driver, the gate driver, and the emission driver, and
wherein the pixel includes:
a first emission transistor connected between a first power voltage line and a driving transistor, and applying a first power voltage to the driving transistor in response to the first emission signal;
and
a second emission transistor connected between the driving transistor and a light emitting element, and applying a driving current generated by the driving transistor to the light emitting element in response to a second emission signal,
wherein the driving controller adjusts voltage application time in which a first power voltage is applied to a driving transistor included in the pixel according to a set luminance level and fixes light emitting time in which a light emitting element included in the pixel emits light regardless of the set luminance level, and
wherein the first emission signal has a first on time in one frame and the second emission signal has a second on time in the one frame, the first on time corresponding to the set luminance level being stored in a lookup table.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 19/264,875Filed 10 Jul 2025 · continuation
Priority: KR 10-2021-01758369 Dec 2021
Published: US 2025/0336348 A130 Oct 2025
Granted: 22 Sep 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

G09G 3/32
Using electroluminescent panels: semiconductive, e.g. using light-emitting diodes [LED]
G09G 3/3233
Using an active matrix: with pixel circuitry controlling the current through the light-emitting element
G09G 2300/0426
Structural details of the set of electrodes: layout of electrodes and connections
G09G 2300/0819
Several active elements per pixel in active matrix panels: used for counteracting undesired variations, e.g. feedback or autozeroing

Family

Application17/968,571Parent of this continuation · filed 18 Oct 2022
US 2025/0336348 A1Pre-grant publication · published 30 Oct 2025
US 12,387,657 B2Parent of this continuation
US 2023/0186832 A1Published application
US 12,743,996 B2This patent

From the US filing history. Foreign family members aren’t listed.