Method for operating a display device

Abstract

A method for operating a display device is provided. The display device includes a display panel including a plurality of pixels and a data driver, the data driver being configured to provide data signals having different voltage levels to all data lines connected to the pixels, the method for operating the display device comprising the following steps: applying a data signal having a first data voltage to all data lines; determining whether a preset sensing current flows in a target wiring; and applying a data signal having a second data voltage to all data lines, wherein the second data voltage is offset from the first data voltage by a specific voltage level.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0080837 filed on Jul. 4, 2019, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a display device and a method of operating the same, and more particularly, to a method of operating a display device that is not driven for a long time. Background Art

[0003] When a display device that was once driven is driven again after having not been used for a long period of time, a long-term storage reliability evaluation has been performed to determine whether the display device can operate normally.

[0004] Recently, two long-term storage reliability evaluations have been used. The first method described below has been used, in which, in a state where the screen of the display device is turned off, a field effect transistor is turned on, a voltage of a light emitting element is fed back, and a distribution of the voltage is analyzed to adjust a voltage level of a data signal and adjust brightness.

[0005] In addition, the second method described below has been used, in which the brightness of the display device is photographed and then the voltage level of the data signal is controlled to adjust the brightness of each position. Summary of the invention

[0006] Example embodiments of the present disclosure provide a method of operating a display device in a case where the display device is inoperable when the display device, which was once driven, is driven again after having not been used for a long time.

[0007] Another object of the present disclosure is to provide a display device in which a function of normally operating the display device is performed.

[0008] However, it should be understood that the objects of the present disclosure will not be limited to the aforementioned objects, but may be variously expanded without departing from the spirit and scope of the present disclosure.

[0009] A display device includes a display panel including a plurality of pixels and a data driver, the data driver being configured to provide data signals having different voltage levels to all data lines connected to the plurality of pixels, and a method of operating the display device according to an example embodiment of the present disclosure includes: applying a data signal having a first data voltage to all data lines; determining whether a preset sensing current flows in at least some of the wirings; and applying a data signal having a second data voltage to all data lines, wherein the second data voltage is offset from the first data voltage by a specific voltage level.

[0010] The display device may further include a current detection unit configured to sense a global current supplied to or flowing out of the display panel, at least some of the wirings may be wirings for connecting the current detection unit and the display panel, and the sensed current may be a global current.

[0011] When a data signal having a first data voltage is applied, a global current may not flow, and when a data signal having a second data voltage is applied, a global current may flow.

[0012] The method may further include determining an offset sign before applying the data signal having the second data voltage to all the data lines.

[0013] The determining of the offset sign may include applying a data signal oscillating in a form in which a level higher than that of the first data voltage and a level lower than that of the first data voltage are alternately repeated.

[0014] The data signal oscillating in the described form may diverge.

[0015] The method may further include determining an offset level before applying the data signal having the second data voltage to all the data lines.

[0016] The second data voltage may have a voltage level at which a light emitting element provided in each of the plurality of pixels emits light.

[0017] The method may further include adjusting the second data voltage after applying the data signal having the second data voltage to each data line.

[0018] Each of the multiple pixels may include: a driving transistor including a first terminal, a second terminal, and a gate terminal connected to a corresponding data line among the data lines; and a light emitting element connected to the second terminal of the driving transistor, wherein the first data voltage has a level higher than a level of a threshold voltage preset in the driving transistor.

[0019] The display device may further include a gamma controller configured to apply the gamma control signal to the data driver, and the gamma controller may determine a voltage level of the second data voltage.

[0020] The at least some of the wirings may include a wiring in which a driving current flowing in each of the plurality of pixels in the display panel flows.

[0021] The first data voltage may be in the range of 2V to 7V, and the second data voltage may be in the range of 7V to 12V.

[0022] The preset sensing current may be in the range of 20A to 30A.

[0023] A display according to another example embodiment of the present disclosure includes: a display panel including a plurality of pixels; a data driver configured to supply data signals having different voltage levels to data lines connected to the plurality of pixels; a scan driver configured to supply scan signals through one or more scan lines connected to the plurality of pixels; a voltage controller configured to supply a current detection control signal to the display panel and generate a voltage control signal; and a current detection unit configured to detect a current supplied to the display panel, wherein, when a light-emitting element provided in each of the plurality of pixels does not emit light even when the data driver supplies a data signal having a first data voltage to each of the plurality of pixels, the data driver supplies a data signal having a second data voltage that is offset from the first data voltage by a specific voltage level.

[0024] The current detection unit may sense a global current supplied to the display panel in response to a current detection control signal.

[0025] The scan driver may include first and second scan lines connected to gate terminals of different transistors provided in each of the plurality of pixels, the scan signal may be transmitted through the first scan line, and the sensing signal may be transmitted through the second scan line.

[0026] The first data voltage may have a preset full white voltage level.

[0027] Additional details of illustrative embodiments are included in the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic block diagram illustrating a display device according to an example embodiment of the present disclosure.

[0029] Figure 2 It is shown Figure 1 A timing diagram of an example of the operation of a display device.

[0030] Figure 3 is a block diagram illustrating a display device according to an exemplary embodiment of the present disclosure.

[0031] Figure 4 It is shown Figure 3 Circuit diagram of a pixel.

[0032] Figure 5 is a graph illustrating a current magnitude of a global current according to a voltage level of a data signal in a display device according to example embodiments.

[0033] Figure 6 is an algorithm flow chart illustrating a method of operating a display apparatus according to an example embodiment.

[0034] Figure 7 It is shown for Figure 6 A timing diagram of the voltage levels of the data signals for each operation. DETAILED DESCRIPTION

[0035] Advantages and features of the present disclosure and methods for achieving the advantages and features of the present disclosure will be more clearly understood through example embodiments described below in conjunction with the accompanying drawings.

[0036] It should be understood that, although terms such as "first", "second", etc. can be used here to describe various components, these components are not limited by these terms. These terms are only used to distinguish one element or component from another element or component. Therefore, without departing from the scope and spirit of the present disclosure, the first component can be named as the second component. Unless otherwise specified, the expression in the singular form is meant to include multiple elements (elements).

[0037] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Like reference numerals represent like elements throughout.

[0038] Figure 1 is a schematic block diagram illustrating a display device according to an example embodiment of the present disclosure. Figure 2 It is shown Figure 1 A timing diagram of an example of the operation of a display device.

[0039] In an example embodiment, the display device 1 may be a quantum dot organic light emitting diode (OLED) display device. However, the present disclosure is not limited thereto, and the display device 1 may be an OLED display device, a liquid crystal display device, a micro light emitting diode (LED) display device, a plasma display device, an electrophoretic display device, a microelectromechanical system (MEMS) display device, or an electrowetting display device.

[0040] Reference Figure 1 and Figure 2 The display device 1 may include a voltage controller 20, a power supply unit 30, a current detection unit 40 and a display panel 10. Figure 1 Only components necessary for the present disclosure are described, and components irrelevant to the description of the present disclosure are omitted. The current detection unit 40 may be included in the power supply unit 30, or may also be implemented outside the power supply unit 30. The display panel 10 includes a plurality of pixels PX that operate based on the high power voltage ELVDD and the low power voltage ELVSS. The display panel 10 and the pixels PX are referred to below. Figure 4 Give a description.

[0041] The power supply unit 30 generates a high power voltage ELVDD and a low power voltage ELVSS based on an input voltage Vin and a voltage control signal VCTRL. The power supply unit 30 may include a boost converter that generates the high power voltage ELVDD, an inverting buck-boost converter that generates the low power voltage ELVSS, and the like. The input voltage Vin provided to the power supply unit 30 may be an alternating current (AC) voltage or a direct current (DC) voltage (such as a battery voltage), and the voltage converter may be an AC-DC converter or a DC-DC converter.

[0042] When the threshold voltage of the driving transistor in the pixel PX changes, the power supply unit 30 may apply the offset data voltage DATA_OFFSET to the pixel PX to achieve grayscale output.

[0043] The current detection unit 40 responds to the indication voltage control period tVC (see Figure 2 ) by sensing the global current GI supplied to or flowing out of the display panel 10 based on the current detection control signal CDCTRL, and generating the current detection signal CDET indicating the average value of the global current GI for each voltage control period tVC.

[0044] The voltage controller 20 generates a current detection control signal CDTRL to change the voltage control period tVC according to whether an image is displayed on the display panel 10, and supplies the current detection control signal CDTRL to the current detection unit 40. In addition, the voltage controller 20 may generate a voltage control signal VCTRL based on the current detection signal CDET supplied from the current detection unit 40, and may supply the voltage control signal VCTRL to the power supply unit 30. The voltage controller 20 may adjust the voltage control signal VCTRL to control the voltage level of the high power voltage ELVDD and / or the low power voltage ELVSS generated by the power supply unit 30.

[0045] Although not shown, the voltage controller 20 may change the voltage control period tVC based on the operability of the voltage controller 20. The voltage control period tVC corresponds to the update period of the power voltages ELVDD and ELVSS. Therefore, the voltage control period tVC corresponds to the period during which the current detection unit 40 provides the average value of the global current GI.

[0046] For example, in the display device 1, one image may be displayed on the display panel 10 during one frame section. Figure 2As shown in , a first image IMG1 may be displayed on the display panel 10 during a first frame segment FP1. A second image IMG2 may be displayed during a second frame segment FP2. A third image IMG3 may be displayed during a third frame segment FP3. A fourth image IMG4 may be displayed during a fourth frame segment FP4.

[0047] In an operation example of the display device 1, the low power voltage ELVSS may be maintained at a negative voltage level while displaying a plurality of images IMG1 to IMG4. The voltage control period tVC in the two-dimensional mode may correspond to one frame segment, and the current detection signal CDET may indicate an average value of the global current GI for each frame segment. For ease of description, as shown in FIG. Figure 2 The current detection signal CDET shown in FIG. 1 includes a pulse for each voltage control period tVC. However, the current detection signal CDET may be a signal having a plurality of bits indicating a digital value corresponding to an average value of the global current GI for each voltage control period tVC.

[0048] The voltage control period tVC may include a sensing section tSEN for sensing the global current GI, and the sensing section tSEN may correspond to a section during which the current detection control signal CDCTRL is activated to a logic high level. Figure 1 The current detection unit 40 can obtain an average value by integrating the global current GI during the sensing section tSEN. For example, when an image is displayed at a frame rate of 120fps (frames per second), the voltage control period tVC (i.e., one frame section) may correspond to 8.33ms, and the sensing section tSEN may be set to 8.22ms. In addition, in some example embodiments, when an image is displayed, since the same image is continuously displayed during one frame section, even when the sensing section tSEN is set to a portion of one frame section, the global current GI can be measured relatively accurately.

[0049] Figure 3 is a block diagram illustrating a display device according to an exemplary embodiment of the present disclosure in more detail. Figure 4 It is shown Figure 3 Circuit diagram of a pixel. Figure 3 and Figure 4 The description of Figure 1 The components are described in detail below, and the reference numerals of some components performing the same functions are changed for the convenience of description.

[0050] Reference Figure 3 and Figure 4The display device 1 includes a display panel 110 including a plurality of pixels PX and a driver configured to drive the display panel 110. The driver includes a scan driver 120, a data driver 130, a gamma controller 140, a timing controller 150, a power supply unit 170, a current detection unit 180, and a voltage controller (VC) 160.

[0051] The display panel 110 may be connected to a data driver 130 of the driver through a plurality of data lines DL, and may be connected to a scan driver 120 of the driver through a plurality of scan lines SL1 and SL2.

[0052] In an example embodiment, the display panel 110 may include a plurality of pixels PX arranged in a row direction and a column direction and arranged in a matrix form. In the present disclosure, the row direction refers to the horizontal direction in the drawings, and the column direction refers to the vertical direction in the drawings (i.e., the direction intersecting the row direction). In an example embodiment, the row direction and the column direction may be understood as relative directions intersecting each other.

[0053] In example embodiments, a row of pixels PX defined by a plurality of pixels PX arranged in a row direction may be connected to the same scan line SL1 or SL2. Also, a column of pixels PX arranged in a column direction among the plurality of pixels PX may be connected to the same data line DL.

[0054] In an example embodiment, the display panel 110 may include a light emitting element that emits light for each pixel PX without a backlight. For example, the light emitting element may be an OLED (see Figure 4 ).

[0055] like Figure 4 As shown in , in an example embodiment, each pixel PX included in the display panel 110 includes a switching transistor Tsw, a driving transistor Tdr, a sensing transistor Tst, a storage capacitor Cst, and an OLED.

[0056] The switching transistor Tsw may include a first terminal connected to the data line DL, a second terminal connected to the first node N1, and a gate terminal connected to the first scan line SL1. Here, the first node N1 may be a node defined by the second terminal of the switching transistor Tsw, the gate terminal of the driving transistor Tdr, and the first electrode of the storage capacitor Cst.

[0057] The switching transistor Tsw may transfer the data signal DATA supplied from the data driver 130 to the storage capacitor Cst and the driving transistor Tdr in response to the scan signal SC applied from the scan driver 120 .

[0058] The storage capacitor Cst may include a first electrode connected to the first node N1 and a second electrode connected to the second node N2. Here, the second node N2 may be a node defined by the second electrode of the storage capacitor Cst, the second terminal of the driving transistor Tdr, the second terminal of the sensing transistor Tst, and the anode electrode of the OLED.

[0059] The storage capacitor Cst can store the data signal DATA transmitted from the switching transistor Tsw. The storage capacitor Cst can store a voltage signal having a level greater than or equal to the threshold voltage VTH of the driving transistor Tdr between the first electrode and the second electrode for a certain time.

[0060] The driving transistor Tdr may include a first terminal to which a high power voltage ELVDD is applied, a second terminal connected to a second node N2, and a gate electrode (i.e., a gate terminal) connected to a first node N1. The driving transistor Tdr may be turned on or off according to a data signal DATA stored in a storage capacitor Cst. For example, when a data signal DATA having a level higher than a level of a threshold voltage VTH of the driving transistor Tdr is applied to the gate terminal, the driving transistor Tdr may be turned on, and a driving current Id may flow from the first terminal of the driving transistor Tdr to the second terminal.

[0061] The OLED may include an anode electrode connected to the second node N2 and a cathode electrode to which the low power voltage ELVSS is applied. The OLED may emit light based on a driving current Id flowing from the high power voltage ELVDD to the low power voltage ELVSS while the driving transistor Tdr is turned on.

[0062] The sensing transistor Tst may include a first terminal to which an initialization voltage VREF is applied, a second terminal connected to a second node N2, and a gate terminal connected to a second scan line SL2. The sensing transistor Tst may supply the initialization voltage VREF transmitted to the first terminal using the second node N2 to which the second terminal of the driving transistor Tdr is connected, or may sense a voltage or current of the second node N2 to which the second terminal of the driving transistor Tdr is connected.

[0063] According to an external compensation algorithm (not shown), the operation time of the sensing transistor Tst may be similar / equal or different from the operation time of the switching transistor Tsw. In an example, the gate terminal of the switching transistor Tsw may be connected to the first scan line SL1, and the gate terminal of the sensing transistor Tst may be connected to the second scan line SL2. In this case, the scan signal SC is transmitted to the first scan line SL1, and the sensing signal SS is transmitted to the second scan line SL2. In another example, the first scan line SL1 connected to the gate terminal of the switching transistor Tsw and the second scan line SL2 connected to the gate terminal of the sensing transistor Tst may be connected together.

[0064] The initialization voltage VREF may be provided from the data driver 130. In this case, the data driver 130 may sense the second node N2 of the pixel PX in real time during a non-display period of an image or during at least one frame section and generate a sensing result. In an example embodiment, the initialization voltage VREF may be about 2V.

[0065] Meanwhile, in some example embodiments, the switching transistor Tsw and the sensing transistor Tst may be turned on at the same time. In this case, the sensing operation by the initialization voltage VREF and the data output operation for outputting the data signal DATA are separated from each other based on the time division method of the data driver 130 .

[0066] In addition, the compensation target according to the sensing result may be a data signal DATA in a digital form, a data signal DATA in an analog form, or a gamma signal supplied by the gamma controller 140. In addition, a compensation circuit configured to generate a compensation signal (or a compensation voltage) based on the sensing result may be included in the data driver 130 or the timing controller 150, or may be implemented as a separate circuit.

[0067] Meanwhile, the structure of the pixel PX including three transistors and one capacitor according to the present exemplary embodiment may be more suitable for manufacturing a large display device, but the present embodiment is not limited to the number of transistors and the number of capacitors constituting the pixel PX. For example, in the exemplary embodiment, the pixel PX may be configured to include seven transistors and one capacitor. In this case, the structure of the pixel PX may be more suitable for manufacturing a small display device.

[0068] The data driver 130 may apply the data signal DATA and the offset data voltage DATA_OFFSET to the display panel 110 through the plurality of data lines DL. The scan driver 120 may apply one or more scan signals SC to the display panel 110 through the plurality of scan lines (i.e., the first scan line SL1 and the second scan line SL2). The gamma controller 140 may apply the gamma control signal to the data driver 130 through the gamma control line.

[0069] The VC 160 generates a current detection control signal CDCTRL so that the voltage control period tVC is changed according to a displayed image, and supplies the generated current detection control signal CDCTRL to the display panel 110. The VC 160 generates a voltage control signal VCTRL based on the current detection signal CDET.

[0070] The timing controller 150 may control the operation of the display apparatus 1. In example embodiments, the VC 160 may be included in the timing controller 150. For example, the timing controller 150 may supply specific control signals to the data driver 130, the gamma controller 140, and the scan driver 120 to control the operation of the display apparatus 1.

[0071] In an example embodiment, the data driver 130, the gamma controller 140, the scan driver 120, and the timing controller 150 may be implemented as one integrated circuit (IC). In another example embodiment, the data driver 130, the scan driver 120, and the timing controller 150 may be implemented as two or more ICs.

[0072] The power supply unit 170 may supply a first power voltage (e.g., a high power voltage ELVDD) and a second power voltage (e.g., a low power voltage ELVSS) to the display panel 110. In an example embodiment, the power supply unit 170 may control the light emission of the display panel 110 by adjusting at least one of the high power voltage ELVDD and the low power voltage ELVSS. The power supply unit 170 may apply a high power voltage ELVDD and a low power voltage ELVSS having a first voltage difference to a plurality of pixels PX so that the plurality of pixels PX do not emit light during a non-emission time. The power supply unit 170 may apply a high power voltage ELVDD and a low power voltage ELVSS having a second voltage difference greater than the first voltage difference to a plurality of pixels PX in a row so that the plurality of pixels PX emit light during an emission time. For example, the first voltage difference may be close to 0V, and the second voltage difference may be a voltage difference sufficient for the OLED to emit light.

[0073] As described above, the current detection unit 180 senses the global current GI supplied to or flowing from the display panel 110 in response to the current detection control signal CDCTRL indicating the voltage control period tVC, and generates the current detection signal CDET indicating the average value of the global current GI for each voltage control period tVC.

[0074] On the other hand, when the display panel 110 that was once operable is driven again after being unused and left for a long time in a high or low temperature state, the threshold voltage VTH of the driving transistor Tdr of each pixel PX may shift. In this case, the pixel PX may not operate at the preset voltage level of the data signal DATA. Figures 5 to 7 A shift of the threshold voltage VTH of the driving transistor Tdr and a method of compensating the data signal DATA according to long-term non-driving are described.

[0075] Figure 5 is a graph illustrating a current magnitude of a global current according to a voltage level of a data signal in a display device according to example embodiments. Figure 6 is an algorithm flow chart illustrating a method of operating a display apparatus according to an example embodiment. Figure 7 It is shown for Figure 6 A timing diagram of the voltage levels of the data signals for each operation. Figure 7 A voltage level V_DL of a data signal flowing in one data line DL is shown for each operation.

[0076] Reference Figure 5 , the threshold voltage VTH of the driving transistor Tdr in the display device 1 may shift. The threshold voltage VTH of the driving transistor Tdr in the display device 1 may shift in a positive direction (i.e., VTH_1) or a negative direction (i.e., VTH_2) according to the time during which the display device 1 is placed in a high temperature or low temperature state.

[0077] As described above, when the data signal DATA having a level less than that of the threshold voltage VTH is supplied to the driving transistor Tdr in each pixel PX, the driving current Id may not flow in the OLED in each pixel PX. In this case, the current magnitude of the global current GI may be about 0A.

[0078] When a data signal DATA having a level greater than or equal to the level of the threshold voltage VTH is supplied to the driving transistor Tdr in each pixel PX, a driving current Id may flow in the OLED in each pixel PX. In this case, as the voltage level of the data signal DATA increases, the current magnitude of the global current GI may increase. Figure 5 As shown in , as the data signal DATA having a level greater than that of the threshold voltage VTH increases, the current magnitude of the global current GI conforms to a linear function. The coefficient of the independent variable of the linear function may be proportional to the number of pixels PX in the display panel 110.

[0079] In an example embodiment, the threshold voltage VTH of the driving transistor Tdr preset in the display panel 110 may be in the range of 2V to 7V. When the threshold voltage VTH is offset in the positive direction, the driving transistor Tdr of each pixel PX may have a first offset threshold voltage VTH_1. When the threshold voltage VTH is offset in the negative direction, the driving transistor Tdr of each pixel PX may have a second offset threshold voltage VTH_2. In an example embodiment, the threshold voltage VTH may be offset in the range of 1V to 5V. For example, in the case where the threshold voltage VTH is offset by 5V, the first offset threshold voltage VTH_1 may be in the range of 7V to 12V. Similarly, the second offset threshold voltage VTH_2 may be in the range of -3V to 2V.

[0080] The above voltage level and offset level of the preset threshold voltage VTH are only illustrative, and the voltage level and offset level of the preset threshold voltage VTH may be different for each display device. The preset threshold voltage VTH may also have a positive voltage level, or may also have a negative voltage level. When the threshold voltage VTH set to have a positive voltage level is offset in a negative direction, the second offset threshold voltage VTH_2 may also have a negative voltage level.

[0081] Reference Figure 6 , a method of operating the display device 1 may include applying a data signal having a first data voltage DATA1 to a data line DL (S100), determining whether a sensing current flows in a target wiring within a preset range (S200), determining an offset sign (S300), determining an offset level (S400), applying a data signal having a second data voltage DATA2 reflecting the offset to the data line DL (S500), and performing fine adjustment (S600).

[0082] In the present disclosure, various operations are described as being performed sequentially according to the flowchart, but it can be obviously performed simultaneously, the order of various operations can be changed, some operations can be omitted, or another operation can be further included between various operations, unless the spirit of the present disclosure is changed.

[0083] First, the step (S100) of applying a data signal having a first data voltage DATA1 to each data line DL is described.

[0084] In an example embodiment, the data driver 130 may apply the first data voltage DATA1 to each data line DL connected to each pixel PX in the display panel 110. In an example embodiment, the first data voltage DATA1 may be within the range of the above-mentioned threshold voltage VTH of the driving transistor Tdr, or have a preset voltage level for driving a full white image. For example, the preset voltage level for driving a full white image may be about 8V. In an example embodiment, the first data voltage DATA1 may be applied to all data lines DL connected to each pixel PX.

[0085] Next, the step ( S200 ) of determining whether a sensing current flows in a target wiring within a preset range is described.

[0086] When the display device 1 has been placed in a high or low temperature state for a long time without being driven, the threshold voltage VTH of the driving transistor Tdr may shift to a voltage level greater than or equal to a preset voltage level for driving a full white image.

[0087] For example, when a data signal having a first data voltage DATA1 is applied to the data line DL and a sensing current flows in a target wiring within a preset range, a data signal having a second data voltage DATA2 reflecting an offset does not need to be applied to the data line DL.

[0088] In an example embodiment, the target wiring is a wiring in which the above-mentioned global current GI flows, and may be a wiring for connecting the current detection unit 180 and the display panel 110. In this case, the sensing current may be the above-mentioned global current GI. For example, when a full white image is displayed, the preset sensing current may be in the range of about 20A to about 30A.

[0089] However, the target wiring is not limited. Any wiring in which the driving current Id of each pixel PX flows can function as the target wiring.

[0090] When a data signal having a first data voltage DATA1 is applied to the data line DL, and a sense current does not flow in a target wiring within a preset range (i.e., the display panel 110 does not operate), a data signal having a second data voltage DATA2 reflecting an offset from the first data voltage DATA1 needs to be applied to the data line DL. Hereinafter, an operation of determining the second data voltage DATA2 is described.

[0091] The step of determining an offset sign (S300) and the step of determining an offset level (S400) are described.

[0092] In an example, in order to determine the offset sign, a data signal oscillating in a form in which a level higher than the level of the first data voltage DATA1 and a level lower than the level of the first data voltage DATA1 are alternately repeated may be applied to each pixel PX. For example, the oscillation may be in a divergent form. While applying a data signal oscillating in this form, it is possible to confirm whether the sensing current increases (or decreases) in the target wiring. For example, when the sensing current increases at a voltage level higher than the voltage level of the first data voltage DATA1, the offset sign may be positive, and when the sensing current increases at a voltage level lower than the voltage level of the first data voltage DATA1, the offset sign may be negative.

[0093] In an example embodiment, to determine the offset level, if the offset sign is positive, the offset level may be increased until a preset sensing current flows so that the display panel 110 displays a full white image, or if the offset sign is negative, the offset level may be decreased until a preset sensing current flows so that the display panel 110 displays a full white image. The minimum offset level may be set to exceed a threshold voltage VTH (e.g., a first offset threshold voltage VTH_1) of the driving transistor Tdr that is offset due to non-driving of the display device.

[0094] Next, the step (S500) of applying the data signal having the second data voltage DATA2 reflecting the offset to the data line DL and the step (S600) of performing the fine adjustment are described.

[0095] In an example embodiment, when the offset sign and the offset level are determined, a data signal having a second data voltage DATA2 reflecting an offset from the first data voltage DATA1 may be applied to the data line DL. The second data voltage DATA2 may have a voltage level at which the OLED of each pixel PX emits light. In an example embodiment, the second data voltage DATA2 may be applied to all data lines DL connected to the pixel PX. In addition, the second data voltage DATA2 applied to all data lines DL may be offset from the first data voltage DATA1 by the same offset level.

[0096] In example embodiments, the second data voltage DATA2 may be determined by the gamma controller 140. The second data voltage DATA2 may be generated by supplying a gamma data signal based on a gamma lookup table (LUT) from the gamma controller 140 to the data driver 130.

[0097] When the display panel 110 does not operate even when the data signal having the second data voltage DATA2 is applied to the data line DL, all processes corresponding to step S200 of determining whether the sensing current flows in the target wiring within a preset range, step S300 of determining the offset sign, step S400 of determining the offset level, and step S500 of applying the data signal having the second data voltage DATA2 reflecting the offset to the data line DL may be performed again.

[0098] Since the threshold voltage VTH of the driving transistor Tdr may be slightly different for each pixel PX, the second data voltage DATA2 may be finely adjusted and applied to each pixel PX.

[0099] In this way, the display device 1 that has been left in a high or low temperature state for a long time without being operated can be operated.

[0100] According to an exemplary embodiment of the present disclosure, even when a display device is driven after being left without being driven for a long period of time, the display device may be operable.

[0101] However, the effects of the present disclosure are not limited to the exemplary embodiments set forth herein, and more various effects are included in the present description.

[0102] Although the example embodiments of the present disclosure have been described with reference to the accompanying drawings, it will be understood by those skilled in the art that the present disclosure may be implemented in other detailed forms without changing the technical spirit and essential features of the present disclosure. Therefore, it should be understood that the example embodiments described herein are illustrative and not restrictive in all aspects. The specific details of other example embodiments are included in the detailed description and the accompanying drawings.

Claims

1. A method of operating a display device, the display device comprising a display panel including a plurality of pixels and a data driver, the data driver being configured to provide data signals having different voltage levels to all data lines connected to the plurality of pixels, the method The following steps are involved: applying a data signal having a first data voltage to each data line; determining whether a preset sensing current flows in the target wiring; as well as When it is determined that the sensing current does not flow in the target wiring, applying a data signal having a second data voltage to each data line, wherein the second data voltage is shifted from the first data voltage by a specific voltage level, wherein the sensing current is a global current supplied to or flowing out of the display panel, and Wherein, when the data signal having the first data voltage is applied, the global current does not flow, and when the data signal having the second data voltage is applied, the global current flows.

2. The method according to claim 1, in, The display device further includes a current detection unit that determines a sensing current by sensing the global current, and The target wiring is a wiring for connecting the current detection unit and the display panel.

3. The method according to claim 1, further comprising: include: After the step of determining whether the preset sensing current flows in the target wiring, an offset sign is determined.

4. The method according to claim 3, in, The determining of the offset sign includes applying a data signal oscillating in a form in which a level higher than a level of the first data voltage and a level lower than the level of the first data voltage are repeated alternately.

5. The method according to claim 4, in, The data signal oscillating in the form diverges.

6. The method according to claim 3, further comprising: include: After determining the offset sign, the offset level is determined.

7. The method according to claim 6, in, The second data voltage includes a voltage level at which a light emitting element disposed in each of the plurality of pixels emits light.

8. The method according to claim 1, further comprising: include: After the step of applying the data signal having the second data voltage to each of the data lines, the second data voltage is adjusted.

9. The method according to claim 1, in, Each pixel of the plurality of pixels comprises: a driving transistor including a first terminal, a second terminal, and a gate terminal connected to a corresponding one of the data lines; and a light emitting element connected to the second terminal of the driving transistor, The first data voltage includes a level higher than a level of a threshold voltage preset in the driving transistor.

10. The method according to claim 1, in, The display device further includes a gamma controller configured to apply a gamma control signal to the data driver, and The gamma controller determines a voltage level of the second data voltage.

11. The method according to claim 1, in, The target wiring includes a wiring in which a driving current flowing in each of the plurality of pixels in the display panel flows.

12. The method according to claim 1, in, The first data voltage is within a range of 2V to 7V, and the second data voltage is within a range of 7V to 12V.

13. The method according to claim 1, in, The preset sensing current is in the range of 20A to 30A.

14. The method according to claim 7, in, The offset level increases until the preset sensing current flows so that the display panel displays a full white image.

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