US-12620366-B2 - Display device with gray voltage for controlling a luminance deviation

US12620366B2US 12620366 B2US12620366 B2US 12620366B2US-12620366-B2

Abstract

Embodiments of the disclosure relate to a display device and a display driving method. A display device according to the disclosure may comprise a display panel where a plurality of subpixels are disposed, a gate driving circuit applying a gate signal to the display panel, a data driving circuit converting image data into a data voltage and applying the data voltage to the display panel, and a timing controller controlling a sensing process for detecting a sensing voltage for a subpixel characteristic value in a blank period and a data update process for updating the image data according to the sensing voltage. The data driving circuit may apply a gray voltage for controlling a luminance deviation in the data update process to the display panel.

Inventors

Kahyung CHOE
YoungHo Kim KIM
Miso Kim
NanYi LEE

Assignees

LG DISPLAY CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20241104
Priority Date: 20231109

Claims (17)

1 . A display device, comprising: a display panel including a plurality of subpixels; a gate driving circuit configured to apply a gate signal to the display panel; a data driving circuit configured to convert image data into a data voltage and apply the data voltage to the display panel; and a timing controller configured to control a sensing process for detecting a sensing voltage for a subpixel characteristic value in a blank period and to control a data update process for updating the image data according to the sensing voltage, wherein the data driving circuit is configured to apply a gray voltage through all data lines of the display panel in a turned-off state of a driving transistor for controlling a luminance deviation in the data update process to the display panel.
2 . The display device of claim 1 , wherein the timing controller includes: an oscillator configured to generate a fixed clock having a constant frequency; a spread clock generator configured to generate a spread clock by varying the frequency of the fixed clock; a multiplexer configured to output the spread clock in a display driving period and the fixed clock in the blank period in response to a selection signal; an internal data enable signal generator configured to generate an internal data enable signal by counting a data enable signal based on the fixed clock received from the multiplexer in the blank period; a switch control signal generator configured to generate a switch control signal by counting the internal data enable signal based on the fixed clock; and an output buffer configured to sample the image data based on the data enable signal in the display driving period and outputting the switch control signal in the blank period.
3 . The display device of claim 2 , wherein the internal data enable signal includes: a sensing data enable signal for controlling the sensing process; and a gray data enable signal for controlling a time of applying the gray voltage.
4 . The display device of claim 3 , wherein the gray data enable signal is generated based on the data enable signal and the sensing data enable signal.
5 . The display device of claim 3 , wherein the sensing process is a real-time sensing process performed in a vertical blank period in a middle of display driving.
6 . The display device of claim 5 , wherein the real-time sensing process includes: a first real-time sensing process where, after a sensing voltage is detected for one or more selected gate lines, a recovery voltage for resetting an applied voltage is applied; or a second real-time sensing process where, after the sensing voltage is detected for the one or more selected gate lines, the recovery voltage for resetting the applied voltage and the gray voltage are sequentially applied.
7 . The display device of claim 6 , wherein the first real-time sensing process and the second real-time sensing process are selected according to a driving frequency.
8 . The display device of claim 7 , wherein the recovery voltage and the gray voltage are generated using the sensing data enable signal.
9 . The display device of claim 7 , wherein the recovery voltage is generated using the sensing data enable signal, and wherein the gray voltage is generated using the gray data enable signal.
10 . The display device of claim 7 , wherein the gray voltage has a level lower than a level of the recovery voltage.
11 . The display device of claim 1 , wherein the blank period has a time interval configured to vary based on a driving frequency.
12 . A method for driving a display device comprising a display panel including a plurality of subpixels, a gate driving circuit configured to apply a gate signal to the display panel, and a data driving circuit configured to convert image data into a data voltage and apply the data voltage to the display panel, the method comprising: in a blank period, a sensing process for detecting a sensing voltage for a subpixel characteristic value for one or more selected gate lines; and a data update process for updating the image data according to a sensing voltage detected in the sensing process, wherein a gray voltage for controlling a luminance deviation is applied through all data lines of the display panel in a turned-off state of a driving transistor in the data update process.
13 . The method of claim 12 , wherein the sensing process includes a first sensing process where a recovery voltage for resetting an applied voltage is applied after the sensing voltage is detected.
14 . The method of claim 12 , wherein the sensing process includes a second sensing process where a recovery voltage for resetting an applied voltage and the gray voltage are sequentially applied after the sensing voltage is detected.
15 . The method of claim 12 , further comprising: generating a fixed clock having a constant frequency; generating a spread clock by varying the frequency of the fixed clock; outputting the spread clock in a display driving period and the fixed clock in the blank period in response to a selection signal; generating an internal data enable signal by counting a data enable signal based on the fixed clock in the blank period; generating a switch control signal by counting the internal data enable signal based on the fixed clock; and sampling the image data based on the data enable signal in the display driving period and transmitting the switch control signal in the blank period.
16 . The method of claim 15 , wherein the internal data enable signal includes: a sensing data enable signal controlling the sensing process; and a gray data enable signal controlling the gray voltage.
17 . The method of claim 16 , wherein the gray data enable signal is generated using the data enable signal and the sensing data enable signal.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority from Korean Patent Application No. 10-2023-0154318, filed on Nov. 9, 2023, which is hereby incorporated by reference for all purposes as if fully set forth herein. BACKGROUND Technical Field Embodiments of the disclosure relate to a display device and a display driving method, and more particularly, to a display device and a display driving method capable of mitigating luminance deviation that occurs while updating a sensing voltage for a characteristic value of a subpixel. Description of the Related Art With the development of the information society, various needs for display devices that display images are increasing, and various types of display devices, such as liquid crystal displays LCDs, organic light emitting diode displays OLEDs, etc., are being utilized. Among these display devices, the organic light emitting display device uses self-emissive organic light emitting diodes, providing advantages, such as a fast response and better contrast ratio, luminous efficiency, luminance, and viewing angle. The display device may include light emitting elements respectively arranged in a plurality of subpixels disposed on a display panel and cause the light emitting diodes to emit light by controlling the voltage applied to the light emitting elements, thereby displaying images while controlling the brightness of each subpixel. In this case, in each subpixel defined on the display panel, a light emitting element and a driving transistor for allowing the light emitting element to emit light are disposed, and a deviation may occur in the characteristic value of the subpixel and mobility or threshold voltage of the driving transistor depending on the driving environment of the display panel. A deviation in luminance between subpixels (luminance non-uniformity) may result, degrading image quality. To reduce the luminance deviation, a characteristic value sensing process is performed which senses the characteristic value of the subpixel in the blank period and compensates for the same. However, a flicker may be perceived due to a gray voltage missing in the process of sensing and updating the characteristic value of the subpixel. BRIEF SUMMARY The inventors of the disclosure have invented a display device and display driving method capable of mitigating a luminance deviation that occurs while updating the data voltage by reflecting a variation in the characteristic value of the subpixel. Embodiments of the disclosure may provide a display device and a display driving method capable of mitigating a luminance deviation that occurs while updating the data voltage by independently controlling a gray voltage in a data update period of updating the data voltage by reflecting a variation in the characteristic value of the subpixel. Further, embodiments of the disclosure may provide a display device and a display driving method capable of reducing an increase in luminance that occurs due to an increase in the blank period in low-frequency driving by applying a gray voltage in a blank period. Further, embodiments of the disclosure may provide a display device and a display driving method capable of mitigating a luminance deviation that occurs while updating a data voltage by independently controlling a gray voltage in a variable refresh rate mode in which the driving frequency is varied. Embodiments of the disclosure may provide a display device comprising a display panel where a plurality of subpixels are disposed, a gate driving circuit applying a gate signal to the display panel, a data driving circuit converting image data into a data voltage and applying the data voltage to the display panel, and a timing controller controlling a sensing process for detecting a sensing voltage for a subpixel characteristic value in a blank period and a data update process for updating the image data according to the sensing voltage, wherein the data driving circuit applies a gray voltage for controlling a luminance deviation in the data update process to the display panel. Embodiments of the disclosure may provide a method for driving a display device including a display panel where a plurality of subpixels are disposed, a gate driving circuit applying a gate signal to the display panel, and a data driving circuit converting image data into a data voltage and applying the data voltage to the display panel, comprising, in a blank period, a sensing process for detecting a sensing voltage for a subpixel characteristic value for one or more selected gate lines and a data update process for updating the image data according to a sensing voltage detected in the sensing process, wherein a gray voltage for controlling a luminance deviation is applied in the data update process. According to embodiments of the disclosure, it is possible to mitigate a luminance deviation that occurs while updating the data voltage by reflecting a variation in the characteristic value of the