Display device and method for driving a display device

Abstract

A display device and a method for driving the display device are provided. The display device can include a display unit, a signal controller, and a sensing unit. The display unit can include pixels. The signal controller can select a first pixel group from the pixels according to an age of the pixels determined based on an image signal. The sensing unit can be electrically connected to each of the display unit and the signal controller, and can sense deterioration information of one or more pixels included in the first pixel group at a vertical blanking period in which the display unit does not display an image.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0116274, filed on September 10, 2020, with the Korean Intellectual Property Office; that Korean Patent Application is incorporated herein by reference. Technical Field

[0003] This technical field relates to display devices and methods for driving display devices. Background Technology

[0004] A display device may include pixels for displaying images. The display device may be an organic light-emitting display device, and each pixel may include an organic light-emitting diode (OLED) and a driving transistor for supplying current to the OLED. Use of the display device may cause degradation of the OLED and driving transistor in the pixel, resulting in pixel degradation. Pixel degradation of the display device may lead to a deterioration in the display quality of the display device. The information disclosed in this Background section is intended to enhance understanding of the background of the described art. The Background section may contain information that does not form prior art known to those skilled in the art. Summary of the Invention

[0005] The implementation example enables real-time sensing and adjustment of pixels.

[0006] The embodiments can display images with uniform brightness regardless of the degradation of the organic light-emitting diodes and / or driving transistors.

[0007] The embodiments may relate to a display device including: a display unit including a plurality of pixels; a sensing unit for sensing degradation information of pixels during vertical blank periods in which no image signal is displayed; and a signal controller for determining pixels for the sensing unit to sense degradation information based on the age of the pixels calculated based on the input image signal.

[0008] Pixels can be divided into multiple blocks, and when the average age of the pixels included in the first block is greater than a predetermined reference value, the signal controller can determine the degradation information of the pixels included in the first block.

[0009] The average age and predetermined reference values ​​can be increased based on the number of image frames displayed on the display unit.

[0010] The average age can increase based on the number of image frames displayed on the display unit based on the image signal, and the predetermined reference value can be constant as the number of image frames increases.

[0011] When the sensing unit senses the degradation information of the pixels included in the first block, the signal controller can reset the average age of the pixels included in the first block, whose degradation information is sensed.

[0012] When the average age of the pixels included in the first block among the blocks is equal to or less than a predetermined reference value, the signal controller can determine to sequentially sense the degradation information of the pixels.

[0013] The pixels can respectively include an organic light emitting diode, a first transistor connected to an anode of the organic light emitting diode, and a storage capacitor connected to a gate of the first transistor, and the degradation information is a threshold voltage of the first transistor.

[0014] The pixels can respectively further include a second transistor connected to the anode of the organic light emitting diode and absorbing a current flowing from the first transistor to the sensing unit, and the sensing unit can sense the current absorbed from the second transistor as the degradation information of the pixel including the second transistor.

[0015] The sensing unit can sense the degradation information during a vertical blanking period in which the pixels do not emit light in one image frame period according to the image signal.

[0016] The display apparatus can further include a data driver for receiving an image data signal from the signal controller and applying a data voltage to the pixels, wherein the signal controller can determine a gray scale compensation value according to the degradation information and the image signal, and can apply the gray scale compensation value to the image signal to generate the image data signal.

[0017] When the age of a first pixel among the pixels is greater than a predetermined reference value, the signal controller can determine to sense the degradation information of the first pixel.

[0018] An embodiment can relate to a method for driving a display apparatus. The method can include the steps of receiving an image signal, calculating ages of a plurality of pixels included in a display unit based on the image signal, determining pixels for sensing degradation information among the pixels according to the ages of the pixels, and sensing the degradation information of the determined pixels.

[0019] When the pixels are divided into a plurality of blocks, the determining of the pixels for sensing the degradation information includes comparing average ages of the pixels included in the respective blocks with a predetermined reference value, and when the average age of the pixels included in a first block among the blocks exceeds the predetermined reference value, determining to sense the degradation information of the pixels included in the first block.

[0020] The average ages and the predetermined reference value can increase according to the number of image frames displayed on the display unit.

[0021] The average age can increase according to a number of image frames displayed on the display unit based on the image signal, and the predetermined reference value can be constant as the number of image frames increases.

[0022] The method can further include resetting the average age of the pixels included in the first block for which the degradation information is sensed, when the degradation information of the pixels included in the first block is sensed.

[0023] Determining the pixels for sensing the degradation information can further include determining to sequentially sense the degradation information of the pixels when the average age of the pixels included in the first block among the blocks is equal to or less than a predetermined reference value.

[0024] The pixels can each include an organic light emitting diode, a first transistor connected to an anode of the organic light emitting diode, and a storage capacitor connected to a gate of the first transistor, and the degradation information can be a threshold voltage of the first transistor.

[0025] Sensing the degradation information of the determined pixels can be performed according to a vertical blanking period in which the pixels do not emit light for one image frame period, based on the image signal.

[0026] Embodiments can relate to a display apparatus including a scan driver to transmit a plurality of scan signals to a plurality of scan lines, a gate driver to transmit a plurality of gate signals to a plurality of gate lines, a data driver to transmit a plurality of data signals to a plurality of data lines, a sensing unit to absorb a current from a plurality of lead-out lines, a display unit including a plurality of pixels connected to a corresponding scan line among the scan lines, a corresponding gate line among the gate lines, a corresponding data line among the data lines, and a corresponding lead-out line among the lead-out lines, and to display an image when the pixels respectively emit light according to the corresponding data signals, and a signal controller to control the scan driver, the gate driver, the data driver, and the sensing unit to sense degradation information in a vertical blanking period in which the pixels do not emit light for one image frame period, based on an input image signal, wherein a scan line for applying a scan signal in a vertical blanking period of a first image frame can be separated from a scan line for applying a scan signal in a vertical blanking period of a second image frame consecutive to the first image frame, with at least one intervening scan line.

[0027] A gate line for applying a gate signal in a vertical blanking period of the first image frame can be separated from a gate line for applying a gate signal in a vertical blanking period of the second image frame, with at least one intervening gate line.

[0028] The pixel can include an organic light emitting diode, a first transistor connected to an anode of the organic light emitting diode and transmitting a driving current, a storage capacitor connected to a gate of the first transistor, a second transistor connected to a data line and a scan line and transmitting a data voltage corresponding to a data signal to the storage capacitor, and a third transistor connected between a lead-out line and the anode of the organic light emitting diode and including a gate connected to a gate line.

[0029] The degradation information can be threshold voltage and electron mobility information of the first transistor.

[0030] The second transistor can be turned on by a scan signal and can transmit a sensing reference voltage transmitted to the data line to the storage capacitor at a vertical blanking period of the first image frame.

[0031] The third transistor can be turned on by a gate signal and can absorb a current to the sensing cell generated by the first transistor according to the sensing reference voltage.

[0032] An embodiment can relate to a display apparatus. The display apparatus can include a display unit, a signal controller, and a sensing unit. The display unit can include pixels. The signal controller can select a first pixel group from the pixels according to an age of the pixels determined based on an image signal. The sensing unit can be electrically connected to each of the display unit and the signal controller and can sense degradation information of one or more pixels included in the first pixel group at a vertical blanking period in which the display unit does not display an image.

[0033] The pixels can be divided into pixel groups.

[0034] The signal controller can select a first pixel group including pixels whose average age is greater than a reference value as the first pixel group.

[0035] Each of the average age and the reference value can increase according to a total number of image frames that have been displayed by the display unit.

[0036] The average age can increase according to a total number of image frames that have been displayed by the display unit. The reference value can be constant when the average age increases.

[0037] The signal controller can reset the average age of the pixels included in the first pixel group when the sensing unit senses the degradation information of the pixels included in the first pixel group.

[0038] The signal controller can control the sensing unit to sequentially sense the degradation information of the pixels of the display unit when the average age of the pixels included in the first pixel group is equal to or less than the reference value.

[0039] Each of the pixels included in the first pixel group can include an organic light emitting diode, a first transistor electrically connected to an anode of the organic light emitting diode, and a storage capacitor electrically connected to a gate of the first transistor. The deterioration information includes a threshold voltage of the first transistor.

[0040] Each of the pixels included in the first pixel group can further include a second transistor electrically connected to the anode and transmitting a current flowing from the first transistor to a sensing unit. The sensing unit can sense the current as a part of the deterioration information.

[0041] The sensing unit can sense the deterioration information according to the image signal in a vertical blanking period in which the first pixel group does not emit light in one image frame period.

[0042] The display apparatus can further include a data driver electrically connected to the signal controller, for receiving the image data signal from the signal controller and applying a data voltage to the pixels. The signal controller can determine a gray scale compensation value according to the deterioration information and the image signal. The signal controller can apply the gray scale compensation value to the image signal to generate the image data signal.

[0043] The signal controller can control the sensing unit to sense the deterioration information of the first pixel when an age of the first pixel among the pixels of the display unit is greater than a reference value.

[0044] An embodiment can relate to a method for driving a display apparatus. The display apparatus can include a display unit. The method can include receiving an image signal; determining an age of a pixel included in the display unit based on the image signal; selecting a first pixel group from the pixels using a signal controller according to the age of the pixel included in the display unit; and sensing deterioration information of one or more pixels included in the first pixel group using a sensing unit electrically connectable to the display unit.

[0045] The method can further include dividing the pixels into pixel groups.

[0046] The method can further include comparing an average age of the pixels included in each of the pixel groups with a reference value. The method can further include selecting the first pixel group as the first pixel group using the signal controller when the average age of the pixels included in the first pixel group exceeds the reference value.

[0047] The average age of the pixels included in each of the pixel groups and the reference value can increase according to a total number of image frames that have been displayed by the display unit.

[0048] The average age of the pixels included in each of the pixel groups can increase according to a total number of image frames that have been displayed by the display unit. The reference value can be constant when the total number of image frames increases.

[0049] The method can further include the step of resetting the average age of the pixels included in the first pixel group when the degradation information of the pixels included in the first pixel group is sensed.

[0050] The method can further include the step of controlling the sensing unit to sequentially sense the degradation information of the pixels included in the display unit when the average age of the pixels included in the first pixel group is equal to or less than a reference value.

[0051] Each of the pixels included in the first pixel group can include an organic light emitting diode, a first transistor electrically connected to an anode of the organic light emitting diode, and a storage capacitor electrically connected to a gate of the first transistor. The degradation information can include a threshold voltage of the first transistor.

[0052] The method can further include dividing the pixels into pixel groups. The method can further include selecting the first pixel group as the first pixel group using the signal controller. Sensing the degradation information of the pixels included in the first pixel group can be performed according to an image signal in a vertical blanking period in which the pixels included in the first pixel group do not emit light.

[0053] An embodiment can relate to a display apparatus including a scan driver to transmit a scan signal to a scan line, a gate driver to transmit a gate signal to a gate line, a data driver to transmit a data signal to a data line, a lead-out line, a sensing unit to receive a current from the lead-out line, a display unit including pixels electrically connected to the scan line, the gate line, the data line, and the lead-out line, and a signal controller to control at least one of the scan driver, the gate driver, the data driver, and the sensing unit to sense degradation information of one or more of the pixels. A first scan line among the scan lines can apply the scan signal in a vertical blanking period of a first image frame. A second scan line among the scan lines can apply the scan signal in a vertical blanking period of a second image frame. The second image frame can follow the first image frame. At least one intervening scan line among the scan lines can be located between the first scan line and the second scan line.

[0054] The first gate line can apply the gate signal in a vertical blanking period of a first image frame. The second gate line can apply the gate signal in a vertical blanking period of a second image frame. The at least one intervening gate line can be located between the first gate line and the second gate line.

[0055] Each of the pixels can include the following elements: an organic light emitting diode; a first transistor electrically connected to an anode of the organic light emitting diode and transmitting a driving current; a storage capacitor electrically connected to a gate of the first transistor; a second transistor electrically connected to a data line and a scan line and transmitting a data voltage corresponding to a data signal to the storage capacitor; and a third transistor electrically connected between a lead-out line and the anode of the organic light emitting diode and including a gate electrically connected to a gate line.

[0056] The deterioration information can include threshold voltage and electron mobility information of one or more first transistors of one or more of the pixels.

[0057] The second transistor can be turned on by a scan signal and can transmit a sensing reference voltage received from the data line to the storage capacitor at a vertical blanking period of the first image frame.

[0058] The third transistor can be turned on by a gate signal and can transmit a current received from the first transistor to the sensing unit according to the sensing reference voltage.

[0059] According to an embodiment, significant screen distortion is prevented.

[0060] According to an embodiment, power consumption for sensing the pixels is minimized.

[0061] According to an embodiment, the display quality of the display apparatus can be satisfactory. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 A block diagram of a display apparatus according to an embodiment is shown.

[0063] Figure 2 A circuit diagram of a pixel of the display apparatus shown in FIG. 1 is shown. Figure 1

[0064] Figure 3 A graph showing periods for sensing pixels in one frame period according to an embodiment is shown.

[0065] Figure 4 A block diagram of a signal controller of the display apparatus shown in FIG. 1 is shown. Figure 1

[0066] A schematic diagram of a pixel age calculator shown in FIG. 1 is shown. Figure 5 Figure 4

[0067] A flowchart of a method for a display apparatus according to an embodiment is shown. Figure 6

[0068] Figure 7 ​​​A display unit of a display apparatus according to an embodiment is shown.

[0069] Figure 8 A diagram of a method for sensing a pixel according to an embodiment is shown.

[0070] Figure 9 A diagram of a method for sensing a pixel according to an embodiment is shown.

[0071] Figure 10 A diagram of a method for sensing a pixel according to an embodiment is shown. DETAILED DESCRIPTION

[0072] Example embodiments are described with reference to the accompanying drawings. The same or similar components can be designated by the same or similar reference numerals. The described embodiments can be modified in various ways.

[0073] Unless explicitly described to the contrary, the word "comprise" and variations such as "comprises" or "comprising" will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0074] Although the terms "first", "second", and the like can be used to describe various elements, these elements should not be limited by these terms. These terms can be used to distinguish one element from another. A first element could be termed a second element without departing from the teachings of one or more embodiments. Describing an element as "first" does not require or imply the presence of a second element or other elements. The terms "first", "second", and the like can be used to distinguish different groups or sets of elements. For simplicity, the terms "first", "second", and the like can be used to refer to "first group (or set)", "second group (or set)", and the like, respectively.

[0075] The term "connected" can mean "electrically connected" or "electrically connected through an intervening transistor". The term "insulated" can mean "electrically insulated" or "electrically isolated". The term "conducting" can mean "electrically conducting". The term "driving" can mean "operating" or "controlling". The term "degraded" can mean "deteriorated". The term "degradation" can mean "deterioration". The term "degradation information" can mean "degradation or deterioration" or "degree of degradation or deterioration". The term "compensation (noun)" can mean "adjustment (noun)". The term "compensation (verb)" can mean "adjustment (verb)". The term "gray scale" can mean "gray scale level". The term "age" can mean "length of operation or use" or "length of operation time". The term "block" can mean "group" or "group of pixels". The term "number" can mean "quantity". The term "sensing" can mean "measuring" and / or "determining". A pixel group can include one or more pixels. A list of materials can mean at least one of the listed materials.

[0076] Figure 1 A block diagram of a display device 10 according to an embodiment is shown.

[0077] The display device 10 includes a display unit (e.g., a display panel) 100, a scan driver 110, a data driver 120, a gate driver 130, and a signal controller 140.

[0078] The display unit 100 includes pixels PX connected to a respective scan line among scan lines SL1 to SLn, a respective data line among data lines DL1 to DLm, and a respective gate line among gate lines GL1 to GLn. The pixels PX respectively emit light according to data signals transmitted through the respective data lines, and thus the display unit 100 can display an image.

[0079] The scan lines SL1 to SLn extend substantially in a row direction and are substantially parallel to each other. The gate lines GL1 to GLn extend substantially in the row direction and are substantially parallel to each other. The data lines DL1 to DLm extend substantially in a column direction and are substantially parallel to each other.

[0080] The scan lines SL1 to SLn and the gate lines GL1 to GLn can be directly located on a same insulating layer. The scan lines SL1 to SLn, the gate lines GL1 to GLn, and the data lines DL1 to DLm can include the same material or different materials (or be formed of the same material or different materials), and can be directly located on a same insulating layer or different insulating layers.

[0081] The scan driver 110 is connected to the display unit 100 through the scan lines SL1 to SLn. The scan driver 110 generates scan signals according to a control signal CONT2 and transmits the scan signals to respective ones of the scan lines SL1 to SLn. The control signal CONT2 is generated and transmitted by the signal controller 140.

[0082] The data driver 120 is connected to the pixels PX of the display unit 100 through the data lines DL1 to DLm. The data driver 120 receives an image data signal DATA and transmits respective data signals to respective ones of the data lines DL1 to DLm according to a control signal CONT1. The control signal CONT1 is generated and transmitted by the signal controller 140.

[0083] The data driver 120 selects a gray voltage to be used to transmit a respective data signal to a data line according to the image data signal DATA. For example, the data driver 120 samples and holds the input image data signal DATA according to the control signal CONT1, and transmits the data signal to the data lines DL1 to DLm. The data driver 120 can apply a data signal within a predetermined voltage range to the data lines when a low-level scan signal is applied.

[0084] The data driver 120 can include a sensing unit 122 for sensing the degradation information of the pixels PX.

[0085] The sensing unit 122 can sense the degradation information of the organic light emitting diode included in the pixel PX. The sensing unit 122 can sense the threshold voltage information and / or the electron mobility information of the driving transistor included in the pixel PX. The sensing unit 122 transmits the degradation information, the threshold voltage information, and / or the electron mobility information as the sensing data DATA SEN to the signal controller 140.

[0086] The sensing unit 122 can be an internal configuration of the data driver 120 or can be separated from the data driver 120.

[0087] The scan driver 110 is connected to the display unit 100 through scan lines SL1 to SLn. The scan driver 110 generates a scan signal according to a control signal CONT2 and transmits the scan signal to a corresponding scan line among the scan lines SL1 to SLn. The control signal CONT2 is generated and transmitted by the signal controller 140.

[0088] The gate driver 130 is connected to the display unit 100 through gate lines GL1 to GLn. The gate driver 130 generates a gate signal according to a control signal CONT3 and transmits the gate signal to a corresponding gate line among the gate lines GL1 to GLn. The control signal CONT3 is generated and transmitted by the signal controller 140.

[0089] The signal controller 140 receives an input image signal IS (from an external source) and an input control signal for controlling a display associated with the image signal IS. The image signal IS can include luminance information related to a gray scale of the pixels PX of the display unit 100.

[0090] The input control signal can include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock signal MCLK, and a data enable signal DE.

[0091] The signal controller 140 generates the control signals CONT1, CONT2, and CONT3 and the image data signal DATA according to the image signal IS, the horizontal synchronization signal Hsync, the vertical synchronization signal Vsync, the main clock signal MCLK, and the data enable signal DE.

[0092] The signal controller 140 generates a control signal CONT1 for controlling the operation of the data driver 120, and transmits the control signal CONT1 to the data driver 120 together with the processed image data signal DATA. The signal controller 140 transmits a control signal CONT2 to the scan driver 110. The signal controller 140 can transmit a control signal CONT3 to the gate driver 130 and can drive the gate driver 130 to sense the degradation information of the pixel PX.

[0093] The signal controller 140 processes the image signal IS according to the operating conditions of the display unit 100 and the data driver 120 based on the image signal IS and an input control signal. The signal controller 140 can generate the image data signal DATA by applying image processing such as gamma correction or luminance compensation to the image signal IS. The signal controller 140 can correct the image signal IS by sensing the data DATA SEN The signal controller 140 can correct the image signal IS according to the degradation information of the organic light emitting diode, the threshold voltage deviation of the associated driving transistor, and / or the electron mobility deviation of the associated driving transistor. If the organic light emitting diode OLED (as shown in Figure 2 The display apparatus 10 can prevent the generation or emission of low luminance light and can display an image having uniform luminance regardless of the threshold voltage deviation and / or the electron mobility deviation of the driving transistor if the organic light emitting diode OLED (as shown in

[0094] Figure 2 A circuit diagram of a pixel PX of the display apparatus 10 according to an embodiment is shown. Figure 1

[0095] The pixel PX can include an organic light emitting diode OLED, a first transistor T1, a second transistor T2, a storage capacitor Cst, and a third transistor T3.

[0096] The organic light emitting diode OLED can be connected between the second node N2 and a wiring of the second power voltage ELVSS. The organic light emitting diode OLED can emit light based on a driving current transmitted through the first transistor T1.

[0097] The first transistor T1 is connected between a wiring of the first power voltage ELVDD and the second node N2, and includes a gate connected to the first node N1. The second node N2 can correspond to an anode of the organic light emitting diode OLED. The first transistor T1 can transmit a driving current to the organic light emitting diode OLED in response to a voltage at the first node N1.

[0098] ​A second transistor T2 is connected between the data line DLj and the first node N1, and includes a gate connected to the corresponding scan line SLi. The second transistor T2 can supply a data voltage or a sensed reference voltage applied to the data line DLj to the first node N1 in response to a scan signal transmitted to the scan line SLi.

[0099] The storage capacitor Cst is connected between the second node N2 and the first node N1. The storage capacitor Cst can temporarily store the voltage supplied through the second transistor T2.

[0100] The third transistor T3 is connected to ( Figure 1 The lead RLj (between lead RL1 and RLm) shown is located between lead RL1 and the second node N2, and may include a gate connected to the corresponding gate line GLi. The third transistor T3 may apply an initialization voltage to the second node N2 in response to a gate signal transmitted through gate line GLi, or it may supply a voltage at the second node N2 to lead RLj. The voltage at the second node N2 may include threshold voltage information of the first transistor T1.

[0101] The lead RLj is connected to the sensing unit 122, and a sensing signal corresponding to the threshold voltage of the first transistor T1 is supplied to the sensing unit 122.

[0102] The operation for sensing degradation information of an organic light-emitting diode (OLED) can be as follows: When the third transistor T3 is turned on by a gate signal transmitted through the gate line GL1, a predetermined current supplied from the sensing unit 122 passes through the third transistor T3 and the OLED and is supplied to the wiring of the second power supply voltage ELVSS. A voltage corresponding to the predetermined current is applied to the OLED, and the sensing unit 122 detects the voltage value as degradation information of the OLED.

[0103] When the power supply voltage is supplied to the display device 10, processing for sensing degradation information of the organic light-emitting diode (OLED) can be performed.

[0104] The operation for sensing the threshold voltage and electron mobility (μ) of the first transistor T1 can be as follows: When the second transistor T2 is turned on by a scan signal transmitted through scan line SLi, the first transistor T1 receives a sensing reference voltage applied through data line DLj. When the third transistor T3 is turned on by a gate signal transmitted through gate line GLi, the current flowing through the first transistor T1 can flow significantly to the sensing unit 122 through lead RLj. The signal controller 140 can determine the change in the threshold voltage and electron mobility (μ) of the first transistor T1 (caused by degradation) based on the decreased current value.

[0105] The transistors T1, T2, and T3 included in the pixel PX can be n-type transistors or p-type transistors. Some of the transistors T1, T2, and T3 included in one pixel PX can be p-type transistors, and the other transistors can be n-type transistors. Some of the transistors T1, T2, and T3 included in one pixel PX can be oxide semiconductor transistors (oxide TFTs), and the other transistors can be transistors including a low-temperature polysilicon (LTPS) semiconductor layer. The transistors T1 and T2 can be oxide semiconductor transistors, and the transistor T3 can be an LTPS transistor. The transistors T1 and T2 can be LTPS transistors, and the transistor T3 can be an oxide semiconductor transistor. The oxide semiconductor layer can include an oxide based on titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), germanium (Ge), zinc (Zn), gallium (Ga), tin (Sn), or indium (In), and a composite oxide thereof (including zinc oxide (ZnO), indium gallium zinc oxide (InGaZnO4), indium zinc oxide (Zn-In-O), zinc tin oxide (Zn-Sn-O), indium gallium oxide (In-Ga-O), indium tin oxide (In-Sn-O), indium zirconium oxide (In-Zr-O), indium zirconium zinc oxide (In-Zr-Zn-O), indium zirconium tin oxide (In-Zr-Sn-O), indium zirconium gallium oxide (In-Zr-Ga-O), indium aluminum oxide (In-Al-O), indium zinc aluminum oxide (In-Zn-Al-O), indium tin aluminum oxide (In-Sn-Al-O), indium aluminum gallium oxide (In-Al-Ga-O), indium tantalum oxide (In-Ta-O), indium tantalum zinc oxide (In-Ta-Zn-O), indium tantalum tin oxide (In-Ta-Sn-O), indium tantalum gallium oxide (In-Ta-Ga-O), indium germanium oxide (In-Ge-O), indium germanium zinc oxide (In-Ge-Zn-O), indium germanium tin oxide (In-Ge-Sn-O), indium germanium gallium oxide (In-Ge-Ga-O), titanium indium zinc oxide (Ti-In-Zn-O), and hafnium indium zinc oxide (Hf-In-Zn-O)).

[0106] Figure 3 A diagram for sensing a period of the pixel PX in one frame period is shown.

[0107] In one frame period (1-frame), an operation for sensing the pixel PX can be performed in a vertical blanking period (e.g., BP1, BP2, BP3, BP4, or BP5), and an operation for sensing the pixel PX is not performed in a period for displaying an image. That is, when the pixel PX does not emit light, degradation information about the pixel PX can be sensed.

[0108] The time for sensing all of the pixels PX in the display unit 100 can be 216 seconds, i.e., 3.6 minutes, at a frame frequency of 60 Hz with a resolution of 8K. When the data driver 120 is driven by applying a data voltage through two pixels PX (e.g., RB or GG) among pixels PX grouped by four pixels (e.g., RGBG), the time for sensing all of the pixels PX in the display unit 100 can be 432 seconds, i.e., 7.2 minutes. Although the pixels PX are degraded for 7.2 minutes, the degradation can not be sensed, and thus a sensing error regarding the pixel degradation can increase. The sensing error can hinder proper correction of the image data. As a result, the image display quality of the display apparatus 10 can be deteriorated.

[0109] According to an embodiment, by sensing the pixels starting from the pixels that can be easily degraded based on the ages of the pixels, a sensing error regarding the pixel degradation can be minimized.

[0110] Figure 4 A block diagram of the signal controller 140 of the display apparatus 10 shown in Figure 1 FIG. 1 is shown according to an embodiment. Figure 5 A schematic diagram of the pixel age calculator 1400 shown in Figure 4 FIG. 1 is shown according to an embodiment. Figure 6 A flowchart of a method for the display apparatus 10 according to an embodiment is shown. Figure 7 A display unit 100 of a display apparatus 10 according to an embodiment is shown.

[0111] As shown in Figure 4 , the signal controller 140 can include a pixel age calculator 1400, a block-wise age calculator 1410, a block-wise age comparator 1420, a block-wise sensing controller 1430, and a compensation controller 1440. One or more of the elements 1400, 1410, 1420, 1430, and 1440 can be separated from the signal controller 140.

[0112] Referring to Figure 4 and Figure 6 , the signal controller 140 receives an image signal IS (in step S100).

[0113] The pixel age calculator 1400 calculates a pixel age AGE PX based on the image signal IS (in step S120). Referring to Figure 5 , the pixel age calculator 1400 can receive the image signal IS and temperature information regarding the display unit 100, and can calculate the pixel age AGE PXThe age calculation algorithm can be used to calculate the pixel age data of pixel PX based on image signal IS and temperature information, using at least one of temperature acceleration factor, grayscale acceleration factor, frame rate, and emission duty cycle dimming. The calculated pixel age data of pixel PX can be stored in memory and can be updated periodically.

[0114] like Figure 7 As shown, the display unit 100 can be divided into blocks, for example, blocks 1-1 to blocks 18-16 (including blocks 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1-8, 1-9, 1-10, 1-11, 1-12, 1-13, 1-14, 1-15, 1-16, ..., 2-2, ..., 3-3, ..., 4-4, ..., 5-5, ..., 6-6, ..., 7-7, ..., 8-8, ..., 9-9, ...). Blocks 10-10, ..., Blocks 11-11, ..., Blocks 12-12, ..., Blocks 13-13, ..., Blocks 14-14, ..., Blocks 15-15, ..., Blocks 16-1, ..., Blocks 16-16, ..., Blocks 17-16, Blocks 18-1, 18-2, 18-3, 18-4, 18-5, 18-6, 18-7, 18-8, 18-9, 18-10, 18-11, 18-12, 18-13, 18-14, 18-15, and 18-16. Each block may include at least two pixels (PX).

[0115] The per-block age calculator 1410 uses the ages of the pixels included in the block to calculate a representative age value for the block (in step S130). The per-block age calculator 1410 can calculate the average age of the pixels PX included in the block as the representative age value for that block. The per-block age calculator 1410 can determine the maximum value AGE among the representative age values ​​of the block. MAX The maximum value AGE can be set. MAX The data is transmitted to each block age comparator 1420, and block information BL about the corresponding block can be transmitted. MAX Provided to each sensor controller 1430.

[0116] Each age comparator 1420 will set the maximum value AGE. MAX The value is compared with a reference value (in step S140). The reference value may increase over time, may increase along with the number of displayed frames, or may be constant.

[0117] When the maximum value AGE MAX When the value is greater than the reference value, each age comparator 1420 will sense the enable signal EN. SENThe output is to each block sensing controller 1430 (in step S150).

[0118] When the maximum value AGE MAX is equal to or less than the reference value, each block age comparator 1420 maintains a normal sensing mode for the sensing unit 122 to sequentially sense all the pixels PX in the vertical blanking period (in step S152).

[0119] In the normal sensing mode, the pixels PX can be sensed in the vertical blanking period in a predetermined order in consecutive frame periods. For example, in a pixel column, eight pixels PX connected to the first to eighth scan lines, respectively, are sequentially sensed in the vertical blanking period of a first image frame in a predetermined order and eight pixels PX connected to the ninth to sixteenth scan lines, respectively, are sequentially sensed in the vertical blanking period of a second image frame immediately following the first image frame. The first to eighth scan lines, which are used to apply a scan signal in the vertical blanking period of the first image frame, are arranged near the ninth to sixteenth scan lines, which are used to apply a scan signal in the vertical blanking period of the second image frame.

[0120] Each block sensing controller 1430 generates a control signal CONT1 SEN for driving the data driver 120, a control signal CONT2 SEN for driving the scan driver 110, and a control signal CONT3 SEN for driving the gate driver 130. Each block sensing controller 1430 outputs these control signals according to a sensing enable signal EN SEN .

[0121] The data driver 120 can apply a sensing reference voltage to a data line connected to a block designated by the control signal CONT1 SEN . The scan driver 110 can sequentially apply a scan signal to a scan line connected to a block designated by the control signal CONT2 SEN . The gate driver 130 can sequentially apply a gate signal to a gate line connected to a block designated by the control signal CONT3 SEN .

[0122] The pixels PX of the designated block can be sensed without following a predetermined order during a vertical blanking period in a continuous frame period. When or after a scan signal is sequentially applied to eight pixels PX (or eight pixel rows) connected to the first to eighth scan lines, respectively, during a vertical blanking period of a first image frame, a scan signal can be sequentially applied to the pixels PX of a designated block (e.g., a block connected to the thirty-third to fortieth scan lines instead of the ninth to sixteenth scan lines) during a vertical blanking period of a second image frame immediately following the first image frame. Two scan line groups (e.g., the first to eighth scan lines and the thirty-third to fortieth scan lines) for receiving a scan signal during the vertical blanking periods of two consecutive image frames can be separated from each other by at least one intervening scan line (e.g., the ninth to thirty-second scan lines).

[0123] When the (maximum) pixel age is less than or equal to the reference value, the display device 10 is in a normal sensing mode for sequentially sensing the degradation information of the pixels PX. When the pixel age is greater than the reference value, the display device 10 can sense the degradation information of the pixels PX having an age equal to or greater than the reference value.

[0124] The degradation information of the pixels PX includes at least one of a threshold voltage of the first transistor T1, electron mobility (μ) information of the first transistor T1, and degradation information of the organic light emitting diode OLED.

[0125] For example, the threshold voltage and the electron mobility (μ) level of the first transistor T1 can be sensed. In a normal sensing mode, for a pixel column, an instance of a scan signal and an instance of a gate signal are sequentially applied to eight pixels PX connected to the first to eighth scan lines, respectively, at a vertical blanking period of a first image frame, so the display apparatus 10 can measure the threshold voltage and the electron mobility (μ) of eight first transistors T1 of the eight pixels PX connected to the first to eighth scan lines, respectively, and an instance of a scan signal and an instance of a gate signal are sequentially applied to eight pixels PX connected to the ninth to sixteenth scan lines, respectively, at a vertical blanking period of a second image frame immediately following the first image frame, so the display apparatus 10 can measure the threshold voltage and the electron mobility (μ) of eight first transistors T1 of the eight pixels PX connected to the ninth to sixteenth scan lines, respectively. When the calculated (maximum) pixel age corresponding to the second image frame is greater than a reference value, an instance of a scan signal and an instance of a gate signal are sequentially applied to pixels PX having a pixel age (equal to or) greater than the reference value (for example, eight pixels PX connected to the thirty-third to fortieth scan lines, not the ninth to sixteenth scan lines) at a vertical blanking period of the second image frame, so the display apparatus 10 can measure the threshold voltage and the electron mobility (μ) of eight first transistors T1 of the eight pixels PX connected to the thirty-third to fortieth scan lines, respectively.

[0126] Accordingly, the sensing unit 122 can sense the threshold voltage and the electron mobility of the first transistor T1 included in the pixels PX located in the designated block.

[0127] The compensation controller 1440 receives the sensing data DATA SEN (in step S160).

[0128] The compensation controller 1440 compensates or adjusts the image data signal DATA by applying the threshold voltage and the electron mobility information of the first transistor T1 (in step S170) and outputs the adjusted image data signal DATA (in step S180). The compensation controller 1440 can adjust the image data signal DATA generated from the image signal IS using the threshold voltage and the electron mobility information of the first transistor T1 included in the pixels PX of the corresponding block. The compensation controller 1440 can output the adjusted image data signal DATA.

[0129] The compensation controller 1440 can determine the threshold voltage and the electron mobility of the first transistor T1 included in the pixels PX of the corresponding block using the sensing data DATA SENa gray scale compensation value corresponding to the inputted image signal IS. The compensation controller 1440 can generate an adjusted image data signal DATA by applying the gray scale compensation value to the inputted image signal IS. The compensation controller 1440 can determine a gray scale compensation value for each gray scale corresponding to a gray scale displayed by the pixel PX. The compensation controller 1440 can determine the gray scale compensation value using a look-up table method or a function algorithm method. The emission efficiency is different for different gray scales, and the degradation amount is different for different gray scales, and thus different compensation values can be applied according to the gray scale displayed. The compensation controller 1440 can determine an optimal compensation value by considering the (accumulated) degradation amount and the gray scale to be displayed in the current frame.

[0130] The compensation controller 1440 outputs a reset signal RESET for resetting the pixel age(s) of the pixel(s) PX included in the compensated block to each block age calculator 1410.

[0131] The signal controller 140 can sense the pixel PX when the pixel age calculated or determined for the pixel PX is greater than a reference value.

[0132] Figure 8 、 Figure 9 and Figure 10 each show a diagram for a method for sensing a pixel PX according to an embodiment.

[0133] The each block age comparator 1420 can compare the reference value with the maximum value AGE MAX The reference value can increase over time, can increase together with the number of display frames, or can be constant.

[0134] Referring to FIGS. 7A and 7B, Figure 8 When the number of frames displayed to the display unit 100 is accumulated, the age reference value 700 is constant. The each block age 710 and 720 calculated by the pixel age calculator 1400 and the each block age calculator 1410 increases as the number of frames is accumulated.

[0135] Until frame a1, the sensing unit 122 can sequentially sense all the pixels PX at the vertical blanking period.

[0136] In frame a1, when the age 710 of the block 1-1 reaches the age reference value 700, SEN the each block age comparator 1420 outputs the sensing enable signal EN Figure 7 to each block sensing controller 1430, and thus the sensing unit 122 can sense the degradation information of the pixels PX included in the block 1-1, for example, the threshold voltage and the electron mobility level of the first transistor T1 of the pixel PX.

[0137] In frame a2, when the compensation controller 1440 compensates the image data signal DATA based on the sensed degradation information, the compensation controller 1440 can output a reset signal RESET to each block age calculator 1410 for resetting the (representative) pixel age of the compensated block 1-1, and each block age calculator 1410 can reset the age 712 of block 1-1.

[0138] Until frame a3 after frame a2, sensing unit 122 can sequentially sense pixels PX except for block 1-1 during the vertical blank period.

[0139] In the same way, in frame a3, when Figure 7 When the age 720 of block 16-1 shown reaches the age reference value 700, each age comparator 1420 will sense the enable signal EN. SEN The output is sent to each sensing controller 1430, so that sensing unit 122 can sense the degradation information of pixel PX included in block 16-1, such as the threshold voltage and electron mobility level of the first transistor T1 of pixel PX.

[0140] In frame a4, when the compensation controller 1440 compensates the image data signal DATA based on the sensed degradation information, the compensation controller 1440 can output a reset signal RESET to each block age calculator 1410 to reset the (representative) pixel age of the compensated block 16-1, and each block age calculator 1410 can reset the age 722 of block 16-1.

[0141] After frame a4, sensing unit 122 can sequentially sense pixels PX except for block 16-1 during the vertical blank period.

[0142] refer to Figure 9 The age reference value 800 increases as the number of frames displayed by the display unit 100 increases. The age 810 calculated by the pixel age calculator 1400 and the per-block age calculator 1410 increases as the number of frames increases.

[0143] Before frame b1, sensing unit 122 can sequentially sense all pixels PX during the vertical blank period.

[0144] In frame b1, when Figure 7 When the age of block 1-1 reaches the age reference value 800, each age comparator 1420 will sense the enable signal EN. SEN The output is sent to each sensing controller 1430, so that sensing unit 122 can sense degradation information about the pixel PX included in block 1-1, such as the threshold voltage and electron mobility level of the first transistor T1 of pixel PX.

[0145] In frame b2, when the compensation controller 1440 compensates the image data signal DATA according to the sensed degradation information, the compensation controller 1440 can output a reset signal RESET for resetting the (representative) pixel age of the compensated block 1-1 to each block age calculator 1410, and each block age calculator 1410 can reset the age 812 of the block 1-1 as well as the age reference value 802.

[0146] After frame b2, the sensing unit 122 can sequentially sense the pixels PX except for the block 1-1 at the vertical blanking period.

[0147] As shown in FIG. 9B, the age reference value 900 increases as the number of frames displayed by the display unit 100 increases. The per-block age 910 calculated by the pixel age calculator 1400 and the per-block age calculator 1410 increases as the number of frames increases. Figure 10

[0148] Since the age 910 of all blocks has not reached the age reference value 900 when the number of frames reaches the predetermined number c1, the per-block age calculator 1410 can reset the age 912 of the blocks as well as the age reference value 902 in the c1th frame.

[0149] In this case, the sensing unit 122 can sequentially sense all the pixels PX at the vertical blanking period.

[0150] According to an embodiment, the sensing of the pixel degradation can start from pixels having a relatively high age, i.e., pixels that have emitted light for a relatively greater number of frames, and the data signal can be adjusted to compensate for the pixel degradation. Advantageously, the pixel degradation can be compensated in time, the power consumption for sensing the pixel degradation can be minimized, and satisfactory image quality can be obtained.

[0151] While example embodiments have been described, actual embodiments are not limited to the described embodiments. Actual embodiments encompass various modifications and equivalent arrangements within the scope of the appended claims.​

Claims

1.A display apparatus comprising: a display unit including pixels; a signal controller configured to compare an average age of the pixels determined based on an image signal with a reference value, and to select a first pixel group as a first pixel cluster when the average age of the pixels included in the first pixel cluster is greater than the reference value; and a sensing unit electrically connected to each of the display unit and the signal controller, configured to sense degradation information of one or more pixels included in the first pixel group at a vertical blanking period in which the display unit does not display an image, wherein the reference value is increased according to a total number of image frames that have been displayed by the display unit, and wherein the signal controller resets the average age of the pixels included in the first pixel cluster when the sensing unit senses the degradation information of the pixels included in the first pixel cluster. 2.The display apparatus of claim 1, wherein the signal controller controls the sensing unit to sequentially sense degradation information of the pixels of the display unit when the average age of the pixels included in the first pixel cluster is equal to or less than the reference value. 3.The display apparatus of claim 1, wherein each of the pixels included in the first pixel cluster includes: an organic light emitting diode; a first transistor electrically connected to an anode of the organic light emitting diode; and a storage capacitor electrically connected to a gate of the first transistor, and the degradation information includes a threshold voltage of the first transistor. 4.The display apparatus of claim 3, wherein each of the pixels included in the first pixel cluster further includes a second transistor electrically connected to the anode and transmitting a current flowing from the first transistor to the sensing unit, and the sensing unit senses the current as a part of the degradation information. 5.The display apparatus of claim 1, wherein the sensing unit senses the degradation information within a vertical blanking period in one image frame period according to the image signal, the first pixel group not emitting light in the vertical blanking period. 6.The display apparatus of any one of claims 1 to 5, further comprising: a data driver electrically connected to the signal controller, configured to receive an image data signal from the signal controller and apply a data voltage to the pixels, wherein the signal controller determines a gray scale compensation value according to the degradation information and the image signal, and the signal controller applies the gray scale compensation value to the image signal to generate the image data signal. 7.The display apparatus of claim 1, wherein the signal controller controls the sensing unit to sense degradation information of a first pixel among the pixels of the display unit when an age of the first pixel is greater than the reference value. 8.A method for driving a display apparatus including a display unit, the method comprising: receiving an image signal; ​ ​ determining an age of a pixel included in the display unit based on the image signal; comparing an average age of the pixel with a reference value, and selecting a first pixel group as a first pixel group when the average age of the pixel included in a first pixel group is greater than the reference value; sensing deterioration information of one or more pixels included in the first pixel group using a sensing unit electrically connected to the display unit; and when the deterioration information of the pixel included in the first pixel group is sensed, resetting the average age of the pixel included in the first pixel group, wherein the reference value is increased according to a total number of image frames that have been displayed by the display unit. ​

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