US-12620341-B2 - Pixel, method for driving the same, and display device including the same

US12620341B2US 12620341 B2US12620341 B2US 12620341B2US-12620341-B2

Abstract

A pixel according to an embodiment of the disclosure includes a light emitting element, a pulse width control circuit that is electrically connected to a data line to which a data voltage is applied, generates an emission control signal having a pulse width depending on the data voltage, and outputs the emission control signal, and a pixel driving circuit that receives the emission control signal and supplies a driving current to the light emitting element for a period according to the pulse width of the emission control signal. According to an embodiment of the disclosure, a pixel displaying images of various grayscales by controlling a period in which the light emitting element emits light, a method for driving the same, and a display device including the same may be provided.

Inventors

Min Kyu Woo
Bon Yong Koo
Hyun Joon Kim
SEON YOUNG CHOI

Assignees

SAMSUNG DISPLAY CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20231115
Priority Date: 20230120

Claims (18)

1 . A pixel comprising: a light emitting element; a pulse width control circuit that is electrically connected to a data line to which a data voltage is applied, generates an emission control signal having a pulse width depending on the data voltage, and outputs the emission control signal; and a pixel driving circuit that receives the emission control signal and supplies a driving current to the light emitting element for a period according to the pulse width of the emission control signal.
2 . The pixel of claim 1 , wherein the pulse width control circuit includes a first capacitor including a first electrode to which the data voltage is applied and a second electrode to which a triangular wave is applied.
3 . The pixel of claim 2 , wherein the pulse width control circuit further includes a first switching element that switches an electrical connection between the first electrode of the first capacitor and the data line.
4 . The pixel of claim 3 , wherein the pulse width control circuit further includes a second switching element including a gate electrode electrically connected to the first electrode of the first capacitor, a source electrode, and a drain electrode, the gate electrode of the second switching element is electrically connected to the first electrode of the first capacitor and the first switching element at a first node, one of the source electrode and the drain electrode of the second switching element is electrically connected to a first power source line to which a first power source voltage is applied, and another one of the source electrode and the drain electrode of the second switching element is electrically connected to a second power source line to which a second power source voltage is applied.
5 . The pixel of claim 4 , wherein the pulse width control circuit further includes a third switching element that switches an electrical connection between the first power source line and the second switching element.
6 . The pixel of claim 5 , wherein the second switching element and the third switching element are electrically connected at a second node, and the emission control signal is output through the second node.
7 . The pixel of claim 6 , wherein the pulse width control circuit further includes a second capacitor including an electrode electrically connected to the second node.
8 . The pixel of claim 5 , wherein the emission control signal has a high level voltage or a low level voltage, one of the high level voltage and the low level voltage is a voltage of the first power source line, and another one of the high level voltage and the low level voltage is a voltage of the second power source line.
9 . The pixel of claim 4 , wherein the light emitting element is electrically connected to a third power source line, the pixel driving circuit includes: a first emission control switching element including a gate electrode to which the emission control signal is input and switching an electrical connection between the first power source line and a fourth node; a fourth switching element including a gate electrode electrically connected to a third node, a source electrode, and a drain electrode; and a fifth switching element that switches an electrical connection between the fourth node and a fourth power source line, one of the source electrode and the drain electrode of the fourth switching element is electrically connected to the fourth node, and another one of the source electrode and the drain electrode of the fourth switching element is electrically connected to a fifth node.
10 . The pixel of claim 9 , wherein the pixel driving circuit further includes a second emission control switching element that switches an electrical connection between the fifth node and the light emitting element.
11 . The pixel of claim 9 , wherein the pixel driving circuit further includes a storage capacitor including an electrode electrically connected to the third node and another electrode electrically connected to the first power source line.
12 . The pixel of claim 9 , wherein the pixel driving circuit further includes a first initialization switching element that switches an electrical connection between the third node and a second power source line to which a second power source voltage is applied, and the gate electrode of the first emission control switching element is electrically connected to the second power source line through the pulse width control circuit.
13 . The pixel of claim 1 , wherein the driving current flowing through the light emitting element flows from a first power source line to which a first power source voltage is applied to the light emitting element via the pixel driving circuit, and a high level voltage of the emission control signal is a voltage applied from the first power source line to the pixel driving circuit via the pulse width control circuit.
14 . A display device comprising: a display panel on which a plurality of pixels including a light emitting element and a plurality of data lines electrically connected to the plurality of pixels are disposed; and a data driving circuit that supplies a data voltage having a voltage level corresponding to grayscale information to at least one data line of the plurality of data lines, wherein each of the plurality of pixels emits light for a period that varies in length according to the grayscale information; and each pixel comprising a pixel driving circuit that receives the emission control signal and supplies a driving current to the light emitting element for a period according to the pulse width of the emission control signal, wherein the emission control signal is dependent on the voltage level of a corresponding one of the connected data lines.
15 . The display device of claim 14 , further comprising: a timing controller that outputs an input image data to the data driving circuit, wherein the input image data includes grayscale information for the each of the plurality of pixels, the data driving circuit outputs the data voltage having the voltage level corresponding to the grayscale information, and the each of the plurality of pixels emits light for a period that varies in length according to the grayscale information included in the input image data.
16 . The display device of claim 14 , wherein a plurality of first scan lines are disposed on the display panel, each of the plurality of first scan lines is electrically connected to ones of the plurality of pixels located in a same pixel row, and the ones of the plurality of pixels located in the same pixel row have different start timings or different end timings of emitting light depending on the data voltage.
17 . The display device of claim 14 , further comprising: a triangular wave output circuit outputting a first voltage or a triangular wave that increases linearly from the first voltage, wherein at least one sweep line to which the triangular wave is applied is disposed on the display panel, the at least one sweep line is electrically connected to the plurality of pixels, a period during which the data voltage is input to the plurality of pixels electrically connected to the at least one sweep line overlaps a period during which the triangular wave output circuit outputs the first voltage, and a period during which the plurality of pixels electrically connected to the at least one sweep line emit light overlaps a period during which the triangular wave output circuit outputs the triangular wave.
18 . An electronic device comprising: a display panel including a pixel to display an image according to an image data; and a host system to output the image data, wherein the pixel comprising: a light emitting element; a pulse width control circuit that is electrically connected to a data line to which a data voltage is applied, generates an emission control signal having a pulse width depending on the data voltage, and outputs the emission control signal; and a pixel driving circuit that receives the emission control signal and supplies a driving current to the light emitting element for a period according to the pulse width of the emission control signal.

Description

CROSS REFERENCE TO RELATED APPLICATION(S) This application claims priority to and benefits of Korean Patent Application No. 10-2023-0008605 under 35 U.S.C. § 119, filed on Jan. 20, 2023, in the Korean Intellectual Property Office (KIPO), the entire contents of which are incorporated herein by reference. BACKGROUND 1. Technical Field Embodiments of the disclosure relate to a pixel, a method for driving the same, and a display device including the same. 2. Description of the Related Art As information technology develops, the importance of a display device, which is a connection medium between a user and information, has been emphasized. In response to this, the use of a non-light emitting type display device such as a liquid crystal display device and the like and a light emitting type display device such as an organic light emitting display device and the like has been increasing. The light emitting type display device may include multiple pixels including one or more light emitting elements. The light emitting type display device may display images of various grayscales by varying a magnitude of a driving current flowing through a light emitting element. However, in case that the display device is used for a long time, a grayscale of an image displayed by a pixel may change due to a change in characteristics of a transistor for supplying the driving current to the light emitting element. This may appear as a phenomenon in which color coordinates preset in the display device are distorted. Accordingly, there is a demand for introducing pixels and display devices displaying images of various grayscales without varying the magnitude of the driving current supplied to the light emitting element. SUMMARY The disclosure provides a pixel displaying images of various grayscales by controlling a length of a period in which a light emitting element emits light, a method for driving the same, and a display device including the same. A pixel according to an embodiment of the disclosure may include a light emitting element, a pulse width control circuit that is electrically connected to a data line to which a data voltage is applied, generates an emission control signal having a pulse width depending on the data voltage, and outputs the emission control signal, and a pixel driving circuit that receives the emission control signal and supplies a driving current to the light emitting element for a period according to the pulse width of the emission control signal. The pulse width control circuit may include a first capacitor including a first electrode to which the data voltage is applied and a second electrode to which a triangular wave is applied. The pulse width control circuit may further include a first switching element that switches an electrical connection between the first electrode of the first capacitor and the data line. The pulse width control circuit may further include a second switching element including a gate electrode electrically connected to the first electrode of the first capacitor, a source electrode, and a drain electrode. The gate electrode of the second switching element may be electrically connected to the first electrode of the first capacitor and the first switching element at a first node. One of the source electrode and the drain electrode of the second switching element may be electrically connected to a first power source line to which a first power source voltage is applied. Another one of the source electrode and the drain electrode of the second switching element may be electrically connected to a second power source line to which a second power source voltage is applied. The pulse width control circuit may further include a third switching element that switches an electrical connection between the first power source line and the second switching element. The second switching element and the third switching element may be electrically connected at a second node. The emission control signal may be output through the second node. The pulse width control circuit may further include a second capacitor including an electrode electrically connected to the second node. The emission control signal may have a high level voltage or a low level voltage. One of the high level voltage and the low level voltage may be a voltage of the first power source line. Another one of the high level voltage and the low level voltage may be a voltage of the second power source line. The light emitting element may be electrically connected to a third power source line. The pixel driving circuit may include a first emission control switching element including a gate electrode to which the emission control signal is input and switching an electrical connection between the first power source line and a fourth node, a fourth switching element including a gate electrode electrically connected to a third node, a source electrode, and a drain electrode, and a fifth switching element that switches an electrical connect