US-20260127999-A1 - DISPLAY DEVICE AND ELECTRONIC DEVICE INCLUDING THE SAME

US20260127999A1US 20260127999 A1US20260127999 A1US 20260127999A1US-20260127999-A1

Abstract

A display device includes a plurality of pixels, each pixel of the plurality of pixels includes a driving transistor, in which the driving transistor receives a data signal and drives a driving current to a light emitting device based on the data signal, a bias transistor which supplies bias power source to the driving transistor, and a scan driver providing a bias scan signal to the bias transistor. The bias scan signal has a first width during a display-scan period and has a second width during a self-scan period, and the second width is different from the first width.

Inventors

Woung Kim

Assignees

SAMSUNG DISPLAY CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20250602
Priority Date: 20241105

Claims (20)

1 . A display device comprising: a plurality of pixels, wherein each pixel of the plurality of pixels includes; a driving transistor, in which a gate electrode of the driving transistor is electrically connected to a data line and receives a data signal through the data line, a first electrode of the driving transistor is electrically connected to a bias power line and receives a bias power source through the bias power line, and a second electrode of the driving transistor is electrically connected to an anode electrode of a light emitting device and drives a driving current to the light emitting device, wherein the light emitting device emits light in proportion to amount of the driving current from the driving transistor; a bias transistor which is turned on in response to a bias scan signal and supplies the bias power source to the first electrode of the driving transistor; and a scan driver generating the bias scan signal and providing the bias scan signal to the bias transistor, wherein a frame includes a display-scan period during which the plurality of pixels receive the data signal and display an image based on the received data signal and a self-scan period during which the plurality of pixels display the image based on a stored data signal received during the display-scan period, in which the bias scan signal has a first width during the display-scan period and has a second width during the self-scan period, and the second width is different from the first width.
2 . The display device according to claim 1 , wherein the second width is narrower than the first width.
3 . The display device according to claim 2 , wherein the stored data signal is received previously during the display-scan period and stored in the plurality of pixels during the self-scan period.
4 . The display device according to claim 3 , wherein the one frame period includes two or more self-scan periods, and the scan driver adjusts a width of the bias scan signal from the first width to the second width during the two or more self-scan periods.
5 . The display device according to claim 4 , wherein the display device further comprises a timing controller which includes a start signal generator, and the start signal generator is configured to generate a scan start signal and provide the scan start signal to the scan driver for controlling the width of the bias scan signal.
6 . The display device according to claim 5 , wherein the start signal generator is configured to receive driving frequency information and determine a number of the self-scan periods included in the one frame period based on the driving frequency information.
7 . The display device according to claim 6 , wherein the scan start signal is configured to control the width of the bias scan signal based on a driving frequency, a dimming level, and an average grayscale of the one frame period.
8 . The display device according to claim 7 , wherein the scan start signal is configured to control the width of the bias scan signal to be decreased as the driving frequency increases.
9 . The display device according to claim 7 , wherein the scan start signal is configured to control the width of the bias scan signal to be decreased as the dimming level increases.
10 . The display device according to claim 7 , wherein the scan start signal is configured to control the width of the bias scan signal to be decreased as the average grayscale increases.
11 . The display device according to claim 1 , further comprising a bias voltage generator generating the bias power source, wherein the bias voltage generator is configured to supply the bias power source through the bias power line, and the bias power source maintains a constant voltage level during one frame period.
12 . The display device according to claim 1 , further comprising a bias voltage generator generating the bias power source, wherein the bias voltage generator is configured to supply the bias power source having a first voltage level to the bias power line during the display-scan period and supply the bias power source having a second voltage level to the bias power line during the self-scan period, and the second voltage level is lower than the first voltage level.
13 . A display device comprising: a plurality of pixels, each pixel of the plurality of pixels including a driving transistor and a bias transistor, wherein the bias transistor is connected between a first electrode of the driving transistor and a bias power line, and upon receiving a bias scan signal, the bias transistor is turned on and supplies a bias power source to first electrode of the driving transistor; and a bias voltage generator configured to change a voltage of the bias power source in accordance with at least one of a dimming level, an average grayscale of one frame period, or a driving frequency, wherein one frame period includes a display-scan period and a plurality of self-scan periods, and during the display-scan period, pixels receive a data signal and display an image based on the received data signal, and during the self-scan periods, pixels display the image based on a stored data signal received during the display-scan period, and wherein the bias voltage generator controls the voltage level of the bias power source during the plurality of self-scan periods to be lower than the voltage level of the bias power source during the display-scan period.
14 . The display device according to claim 13 , wherein the bias voltage generator is configured to control the voltage level of the bias power source to be lower as the driving frequency increases.
15 . The display device according to claim 13 , wherein the bias voltage generator is configured to control the voltage level of the bias power source to be lower as the dimming level increases.
16 . The display device according to claim 13 , wherein the bias voltage generator is configured to control the voltage level of the bias power source to be lower as the average grayscale of the one frame increases.
17 . The display device according to claim 13 , wherein, during the display-scan period, the plurality of pixels receive a data signal and display an image based on the received data signal, and during the self-scan period, the plurality of pixels display the image based on a stored data signal received during the display-scan period.
18 . The display device according to claim 17 , wherein the display device further comprises a scan driver, and the scan driver is configured to adjust a width of the bias scan signal during two or more self-scan periods of the one frame period.
19 . The display device according to claim 18 , wherein the display device further comprises a timing controller which includes a start signal generator, and the start signal generator is configured to generate a scan start signal and provides the scan start signal to the scan driver for controlling the width of the bias scan signal.
20 . An electronic device comprising: a processor; and a display device comprising, a plurality of pixels, each pixel of the plurality of pixels including a driving transistor and a bias transistor, wherein the bias transistor is connected between a first electrode of the driving transistor and a bias power line, and upon receiving a bias scan signal, the bias transistor is turned on and supplies a bias power source to first electrode of the driving transistor, and a gate driver supplying the bias scan signal having a first width during a display-scan period and a second width different from the first width during a self-scan period, wherein one frame period includes a display-scan period and a self-scan period, and during the display-scan period, pixels receive a data signal and display an image based on the received data signal, and during the self-scan period, pixels display the image based on a stored data signal received during the display-scan period, and wherein the processor transmits a command to the display device for controlling the gate driver of the display device to supply the bias scan signal having different widths during the display-scan period and the self-scan period.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority under 35 U.S.C. § 119(a) to Korean Patent Application No. 10-2024-0155524, filed on Nov. 5, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. TECHNICAL FIELD Embodiments of the present inventive concept relate to a display device, a method for driving the display device, and an electronic device including the display device. More particularly, the display device improves display quality by reducing luminance variation at different driving conditions. DISCUSSION OF RELATED ART Modern display devices are becoming important elements which connect various electrical media to users and provide high-quality video information. The display devices may include a plurality of pixels which emit light with predetermined luminance. Because maintaining stable luminance level at various operating conditions is important for improving display quality of the display devices, pixels may be controlled differently at different driving conditions. The display devices may include a liquid crystal display device, an organic light emitting display device, and an inorganic light emitting display device. SUMMARY A display device includes a plurality of pixels, each pixel of the plurality of pixels includes a driving transistor, in which a gate electrode of the driving transistor is electrically connected to a data line and receives a data signal through the data line, a first electrode of the driving transistor is electrically connected to a bias power line and receives a bias power source through the bias power line, and a second electrode of the driving transistor is coupled to an anode electrode of a light emitting device and drives a driving current to the light emitting device, wherein the light emitting device emits light in proportion to amount of the driving current from the driving transistor, and a bias transistor which is turned on in response to a bias scan signal and supplies the bias power source to the first electrode of the driving transistor, and a scan driver generating the bias scan signal and providing the bias scan signal to the bias transistor, the bias scan signal has a first width during a display-scan period and has a second width during a self-scan period, and the second width is different from the first width. The second width is narrower than the first width. one frame period includes the display-scan period and the self-scan period which immediately follows the display-scan period, and during the display-scan period, pixels receives a data signal and displays an image based on the received data signal, and during the self-scan period following the display-scan period, pixels displays the image based on a stored data signal previously received during the display-scan period. The one frame period includes two or more self-scan periods, and the scan driver adjusts a width of the bias scan signal from the first width to the second width during the two or more self-scan periods. The display device further includes a timing controller, and the timing controller includes a start signal generator, and the start signal generator generates a scan start signal and provides the scan start signal to the scan driver for controlling the width of the bias scan signal. The start signal generator receives driving frequency information and determines a number of the self-scan periods included in the one frame period based on the driving frequency information. The scan start signal controls the width of the bias scan signal based on a driving frequency, a dimming level, and an average grayscale of the one frame period. The scan start signal controls for the width of the bias scan signal to be decreased as the driving frequency increases. The scan start signal controls the width of the bias scan signal to be decreased as the dimming level increases. The scan start signal controls the width of the bias scan signal to be decreased as the average grayscale increases. The display device further includes a bias voltage generator generating the bias power source, wherein the bias voltage generator is configured to supply the bias power source through the bias power line, and the bias power source maintains a constant voltage level during the one frame period. The display device further includes a bias voltage generator generating the bias power source, wherein the bias voltage generator is configured to supply the bias power source having a first voltage to the bias power line during the display-scan period and supply the bias power source having a second voltage to the bias power line during the self-scan period, and the second voltage is lower than the first voltage. According to an embodiment, a display device includes a plurality of pixels, each pixel of the plurality of pixels includes a driving transistor and a bias transistor, wherein the bias transistor is connected between a