Display device and method of driving same

Abstract

The present disclosure relates to a display device and a method of driving the display device. More specifically, the present disclosure provides a display device including: a display panel including sub-pixels disposed in a display area and virtual sub-pixels disposed in an outer area; a driving circuit configured to output a sensing data voltage for sensing a first one of the sub-pixels and a first one of the virtual sub-pixels; and a sensing circuit configured to acquire, as a sensing voltage, a third sensing value obtained by adding a first sensing value applied to the sensing node of the first sub-pixel and a second sensing value applied to the sensing node of the first virtual sub-pixel.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2023-0175400, filed on December 6, 2023, which is hereby incorporated by reference as if fully set forth herein. Technical Field

[0003] The present disclosure relates to a display device and a method of driving the display device. Background Art

[0004] With the development of information technology, the market for display devices as a communication medium between users and information is growing. Therefore, display devices such as light emitting display (LED) devices, quantum dot display (QDD) devices and liquid crystal display (LCD) devices are increasingly used.

[0005] The above-mentioned display device includes: a display panel including sub-pixels, a driver outputting a driving signal for driving the display panel, and a power supply for generating power to be supplied to the display panel or the driver.

[0006] In such a display device, when driving signals such as a scan signal and a data signal are supplied to sub-pixels formed in a display panel, selected sub-pixels transmit light or directly emit light, thereby displaying an image.

[0007] However, as the resolution and driving frequency of the display device increase, there may not be enough time to perform the sub-pixel sensing operation for performing compensation. Therefore, a display device is needed that can reduce the time required to perform sub-pixel sensing even at a high driving frequency or high resolution. Summary of the invention

[0008] Accordingly, the present disclosure is directed to a display device and a method of driving the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.

[0009] The purpose of the present disclosure is to reduce the time required to obtain a sensing voltage so that degradation of elements included in a display panel can be sensed and compensated even in a high-resolution, high-frequency, and high-pixel-per-inch (PPI) model, and to ensure the time required for accurate compensation based on minimization of the sensing time to improve compensation performance.

[0010] Additional advantages, purposes and features of the present disclosure will be described in part in the following description, and in part will become apparent to those skilled in the art after reviewing the following, or may be understood from the practice of the present disclosure. The purposes and other advantages of the present disclosure may be realized and obtained through the structures specifically indicated in the written description and claims and the drawings.

[0011] To achieve these objectives and other advantages, and in accordance with the purposes of the present disclosure, as embodied and broadly described herein, a display device includes: a display panel including sub-pixels arranged in a display area and virtual sub-pixels arranged in an external area; a driving circuit configured to output a sensing data voltage for sensing a first sub-pixel in the sub-pixels and a first virtual sub-pixel in the virtual sub-pixels; and a sensing circuit configured to obtain a third sensing value as a sensing voltage, the third sensing value being obtained by adding a first sensing value applied to a sensing node of the first sub-pixel and a second sensing value applied to a sensing node of the first virtual sub-pixel.

[0012] The second sensing value applied to the first dummy sub-pixel may be used as a constant current source for increasing current when the first sensing value applied to the sensing node of the first sub-pixel is sensed.

[0013] The display device may further include a compensator configured to generate a compensation value for compensating the first subpixel based on the first sensing value excluding the second sensing value from the sensing voltage.

[0014] The sensing circuit may acquire a sensing value from one of the virtual sub-pixels or acquire sensing values ​​from a plurality of virtual sub-pixels in response to at least one of a resolution, a frequency, or a PPI of the display panel.

[0015] When the position where the protection image displayed based on the sub-pixel display is displayed is moved, the virtual sub-pixel may display a black image.

[0016] In another aspect of the present disclosure, a display device includes: a display panel including sub-pixels arranged in a display area and virtual sub-pixels arranged in an external area; a driving circuit configured to: display a protection image based on the sub-pixels, move a display position where the protection image is displayed, and move a position of a black image displayed on at least one of the virtual sub-pixels whenever the display position of the protection image is moved; and a sensing circuit configured to: obtain a first sensing value from a first sub-pixel among the sub-pixels, obtain a second sensing value from a first virtual sub-pixel displaying a black image among the virtual sub-pixels, and obtain a third sensing value as a sensing voltage, the third sensing value being obtained by adding the first sensing value to the second sensing value.

[0017] The display device may further include a compensator configured to generate a compensation value for compensating the first subpixel based on the first sensing value excluding the second sensing value from the sensing voltage.

[0018] The sensing circuit may acquire a sensing value from one of the virtual sub-pixels or acquire sensing values ​​from a plurality of virtual sub-pixels in response to at least one of a resolution, a frequency, or a PPI of the display panel.

[0019] In another aspect of the present disclosure, a method for driving a display device includes: displaying a protection image based on sub-pixels set in a display area of ​​a display panel of the display device, and moving a display position where the protection image is displayed; displaying a black image on at least one virtual sub-pixel set in an outer area of ​​the display panel, and moving the position of the black image whenever the display position of the protection image is moved; acquiring a first sensing value from a first sub-pixel among the sub-pixels, and acquiring a second sensing value from a first virtual sub-pixel displaying the black image among the virtual sub-pixels, and acquiring a third sensing value as a sensing voltage, the third sensing value being obtained by adding the first sensing value to the second sensing value; and generating a compensation value for compensating at least one sub-pixel among the sub-pixels based on the first sensing value excluding the second sensing value from the sensing voltage.

[0020] Acquiring the sensing voltage may include acquiring a sensing value from one of the virtual sub-pixels or acquiring sensing values ​​from a plurality of virtual sub-pixels in response to at least one of a resolution, a frequency, or a PPI of the display panel.

[0021] It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. In the drawings:

[0023] Figure 1 is a block diagram schematically showing a light emitting display device, Figure 2 It is schematically shown Figure 1 The sub-pixel configuration diagram shown in FIG. Figure 3 is a diagram showing a pixel composed of sub-pixels;

[0024] Figure 4 and Figure 5 is a diagram showing a configuration of a gate-in-panel type gate driver, and Figure 6 is a diagram showing an example of arrangement of a gate-in-panel type gate driver;

[0025] Figure 7 is a diagram schematically showing a sub-pixel and a data driver according to a first example of an embodiment, Figure 8 is a diagram schematically showing a sub-pixel and a data driver according to a second example of an embodiment, and Fig. 9 is a waveform diagram showing a sensing period and a display period according to an embodiment;

[0026] Fig.10 is a diagram showing some of the components included in the data driver according to an embodiment in more detail, and Fig.11 and Fig.12 is a diagram illustrating a method of sensing a display panel according to an embodiment;

[0027] Fig.13 is a diagram showing a dummy pixel group included in a display panel of a light emitting display device according to an embodiment, and Figures 14 to 16 is a diagram showing a track driving method of a display panel according to an embodiment;

[0028] Fig.17 is a diagram showing the position of a sensing target sub-pixel of a display panel according to an embodiment, Fig.18 yes Fig.17 The equivalent circuit diagram of the Cth virtual sub-pixel and the Kth sub-pixel is shown in FIG. Fig.19 is shown for Fig.18 The driving waveform of the sub-pixel obtaining the sensing voltage is shown in FIG. Fig. 20 It is shown that Fig.18 A diagram showing the path for a sub-pixel to obtain a sensing voltage, and Fig.21 is a diagram showing a difference between a sensed value of a Cth dummy sub-pixel and a sensed value of a Kth sub-pixel;

[0029] Fig. 22 and Fig.23 is a diagram showing advantages of a sensing voltage acquisition method according to an embodiment, and Fig.24 is a diagram showing a driving environment to which a sensing voltage acquisition method according to an embodiment may be applied; and

[0030] Fig.25 is a flowchart showing a sensing voltage acquisition method according to a first example, and Fig.26 is a flowchart illustrating a sensing voltage acquisition method according to a second example. DETAILED DESCRIPTION

[0031] The display device according to the present disclosure may be implemented as a television system, an image player, a personal computer (PC), a home theater, an automotive electrical device, a smart phone, etc., but is not limited thereto. The display device according to the present disclosure may be implemented as a light emitting display (LED) device, a quantum dot display (QDD) device, a liquid crystal display (LCD) device, etc. However, for ease of description, as an example, a light emitting display device based on direct light emission of an inorganic light emitting diode or an organic light emitting diode will be described below.

[0032] Figure 1 is a block diagram schematically showing a light emitting display device, Figure 2 It is schematically shown Figure 1 The sub-pixel configuration diagram shown in FIG. Figure 3 is a diagram showing a pixel composed of sub-pixels.

[0033] like Figure 1 , Figure 2 and Figure 3 As shown, the light emitting display device may include an image provider 110, a timing controller 120, a gate driver 130, a data driver 140, a display panel 150, a power supply 180, and the like.

[0034] The image provider 110 (set or host system) may output various driving signals as well as an externally provided image data signal or an image data signal stored in an internal memory. The image provider 110 may supply a data signal and various driving signals to the timing controller 120 .

[0035] The timing controller 120 may output a gate timing control signal GDC for controlling the operation timing of the gate driver 130, a data timing control signal DDC for controlling the operation timing of the data driver 140, and various synchronization signals. The timing controller 120 may supply the data signal DATA supplied from the image provider 110 together with the data timing control signal DDC to the data driver 140. The timing controller 120 may be implemented in the form of an integrated circuit (IC) and mounted on a printed circuit board, but is not limited thereto.

[0036] The gate driver 130 may output a gate signal (or a gate voltage) in response to a gate timing control signal GDC supplied from the timing controller 120. The gate driver 130 may supply the gate signal to the sub-pixels included in the display panel 150 through the gate lines GL1 to GLm. The gate driver 130 may be implemented in the form of an IC or directly formed on the display panel 150 in a gate-in-panel structure, but is not limited thereto.

[0037] The data driver 140 may sample and latch the data signal DATA in response to the data timing control signal DDC supplied from the timing controller 120, convert the digital data signal into an analog data voltage based on the gamma reference voltage, and output the analog data voltage. The data driver 140 may supply the data voltage to the sub-pixels included in the display panel 150 through the data lines DL1 to DLn. The data driver 140 may be implemented in the form of an integrated circuit (IC) and mounted on the display panel 150 or on a printed circuit board, but is not limited thereto.

[0038] The power supply 180 may generate a high-level first power and a low-level second power based on an external input voltage supplied from the outside. The power supply 180 may output the first power through the first power line EVDD and output the second power through the second power line EVSS. The power supply 180 may generate and output voltages (e.g., a scan high voltage and a scan low voltage) required to drive the gate driver 130 and voltages (e.g., a drain voltage and a half-drain voltage) required to drive the data driver 140, as well as the first power and the second power.

[0039] The display panel 150 may display an image in response to a drive signal including a scan signal and a data voltage, a first power, and a second power. The sub-pixels of the display panel 150 may directly emit light. The display panel 150 may be manufactured based on a rigid or flexible substrate such as glass, silicon, polyimide, etc. For example, one sub-pixel SP may be connected to a first data line DL1, a first gate line GL1, a first power line EVDD, and a second power line EVSS and may include a pixel circuit including a switching transistor, a driving transistor, a capacitor, an organic light emitting diode, etc.

[0040] The sub-pixel SP used for the light-emitting display device directly emits light, so its circuit configuration is complicated. In addition, there are various compensation circuits that compensate not only for the degradation (threshold voltage, mobility, etc.) of the organic light-emitting diode that emits light, but also for the degradation of the driving transistor that supplies the driving current required to drive the organic light-emitting diode. Therefore, the sub-pixel SP is simply shown in the form of a block.

[0041] The luminous sub-pixels may be composed of red pixels, green pixels, and blue pixels, or of red pixels, green pixels, blue pixels, and white pixels. For example, one pixel P may include a red sub-pixel SPR connected to a first data line DL1, a white sub-pixel SPW connected to a second data line DL2, a green sub-pixel SPG connected to a third data line DL3, and a blue sub-pixel SPB connected to a fourth data line DL4. Additionally, the red sub-pixel SPR, the white sub-pixel SPW, the green sub-pixel SPG, and the blue sub-pixel SPB may be connected to a first reference line VREF1 in common. The first reference line VREF1 may be used to sense degradation of an element included in one of the red sub-pixel SPR, the white sub-pixel SPW, the green sub-pixel SPG, and the blue sub-pixel SPB, which will be described below.

[0042] Meanwhile, the timing controller 120, the gate driver 130, and the data driver 140 have been described as separate components. However, depending on the implementation method of the light-emitting display device, one or more of the timing controller 120, the gate driver 130, and the data driver 140 may be integrated into a single IC. In addition, the timing controller 120, the gate driver 130, the data driver 140, the power supply 180, and the display panel 150 are components for displaying an image and may be defined as a display module.

[0043] In addition, as an example, a pixel P in which red subpixel SPR, white subpixel SPW, green subpixel SPG, and blue subpixel SPB are sequentially arranged has been illustrated. However, the arrangement order and direction of the subpixels may vary according to an implementation method of the light emitting display device.

[0044] Figure 4 and Figure 5 is a diagram showing a configuration of a gate-in-panel type gate driver, and Figure 6 is a diagram showing an example of arrangement of a gate-in-panel type gate driver.

[0045] like Figure 4As shown, the gate-in-panel type gate driver may include a shift register 131 and a level shifter 135. The level shifter 135 may generate a driving clock signal Clk and a start signal Vst based on signals and voltages output from the timing controller 120 and the power supply 180.

[0046] The shift register 131 operates based on the signals Clk and Vst output from the level shifter 135 and can output scanning signals Gate[1] to Gate[m] for turning on or off transistors formed in the display panel. The shift register 131 can be in the form of a thin film having an in-panel gate structure on the display panel.

[0047] like Figure 4 and Figure 5 As shown, unlike the shift register 131, the level shifter 135 may be independently formed in the form of an IC, or may be included in the power supply 180. However, this is merely an example, and the present disclosure is not limited thereto.

[0048] like Figure 6 As shown, the shift registers 131a and 131b that output gate signals in the gate-in-panel type gate driver may be disposed in the non-display area NA of the display panel 150. For example, the shift registers 131a and 131b are disposed in the left non-display area and the right non-display area NA of the display panel 150, but the shift registers 131a and 131b may also be disposed in the upper non-display area and the lower non-display area NA of the display panel 150, or may be disposed in the display area AA of the display panel 150.

[0049] Figure 7 is a diagram schematically showing a sub-pixel and a data driver according to a first example of an embodiment, Figure 8 is a diagram schematically showing a sub-pixel and a data driver according to a second example of an embodiment, and Fig. 9 is a waveform diagram showing a sensing period and a display period.

[0050] like Figure 7 As shown, according to the first example, one sub-pixel SP may include a switching transistor SW, a driving transistor DT, a sensing transistor ST, a capacitor CST, and an organic light emitting diode OLED.

[0051] The driving transistor DT may include a gate electrode connected to a first electrode of the capacitor CST, a first electrode connected to a first power line EVDD, and a second electrode connected to an anode of the organic light emitting diode OLED. The capacitor CST may have a first electrode connected to the gate electrode of the driving transistor DT and a second electrode connected to an anode electrode of the organic light emitting diode OLED. The organic light emitting diode OLED may have an anode connected to a second electrode of the driving transistor DT and a cathode connected to a second power line EVSS.

[0052] The switching transistor SW may include a gate electrode connected to a first scan line Gate1 included in the first gate line GL1, a first electrode connected to a first data line DL1, and a second electrode connected to a gate electrode of the driving transistor DT. The sensing transistor ST may include a gate electrode connected to a second scan line Gate2 included in the first gate line GL1, a first electrode connected to a first reference line VREF1, and a second electrode connected to an anode of the organic light emitting diode OLED.

[0053] The sensing transistor ST is a compensation circuit added to compensate for degradation of the driving transistor DT or the organic light emitting diode OLED. The sensing transistor ST can implement physical threshold voltage sensing based on the source follower operation of the driving transistor DT. The sensing transistor ST can be operated to obtain a sensing voltage through a sensing node defined between the driving transistor DT and the organic light emitting diode OLED.

[0054] According to an embodiment, the data driver 140 may include a driving circuit 141 for driving the sub-pixel SP and a sensing circuit 145 for sensing the sub-pixel SP. The driving circuit 141 may be connected to the first data line DL1 through the first data channel DCH1. The driving circuit 141 may output a data voltage Vdata for driving the sub-pixel SP through the first data channel DCH1.

[0055] The sensing circuit 145 may be connected to the first reference line VREF1 through the first sensing channel SCH1. The sensing circuit 145 may acquire the sensing voltage Vsen sensed from the sub-pixel SP through the first sensing channel SCH1. The sensing circuit 145 may acquire the sensing voltage Vsen based on a current sensing method or a voltage sensing method.

[0056] like Figure 8 As shown, according to the second example, the first gate line GL1 can be integrated into one. That is, unlike the first example, the first gate line GL1 may not be divided into the first scan line and the second scan line. In this case, the switching transistor SW and the sensing transistor ST are commonly connected to the first gate line GL1, and thus can be turned on or off at the same time.

[0057] like Fig. 9 As shown, the light emitting display device according to the embodiment may adopt driving modes corresponding to the first driving period PWR_ON, the second driving period DISPLAY, and the third driving period PWR_OFF, respectively, when operating to drive the display panel.

[0058] The first driving period PWR_ON may correspond to a driving start period in which power is applied to the display panel; the second driving period DISPLAY may correspond to a panel driving period in which operations such as displaying an image are performed after power is applied to the display panel; and the third driving period PWR_OFF may correspond to a driving end period in which the power applied to the display panel is cut off. At the same time, the third driving period PWR_OFF is a period in which the display panel is driven for a certain period of time while displaying black so that a sensing operation of the display panel can be performed. That is, it should be noted that during the third driving period PWR_OFF, the power applied to the display panel, etc. is not completely cut off. In this way, it appears to the user that the light-emitting display device is immediately turned off in response to a shutdown instruction, but the light-emitting display device displays black (does not display anything) when performing a sensing operation before finally turning off, but remains turned on.

[0059] The light-emitting display device according to the embodiment can sense the display panel in at least one of the first driving period PWR_ON, the second driving period DISPLAY (for example, during the BLK period) and the third driving period PWR_OFF. For example, in the second driving period DISPLAY, the blank period BLK included in the vertical synchronization signal Vsync can be defined as the sensing period PSP, and the active period ACT included in the vertical synchronization signal Vsync can be defined as the display period DSP.

[0060] Fig.10 is a diagram showing some of the components included in the data driver according to an embodiment in more detail, and Fig.11 and Fig.12 A diagram showing a method of sensing a display panel according to an embodiment. Figure 7 The structure of the sub-pixel SP is shown.

[0061] As in Fig.10 In the illustrated embodiment, the driving circuit 141 may include a digital-to-analog converter DAC to output a sensing data voltage, a black data voltage, or a display data voltage through the first data line DL1. The sensing circuit 145 may include a first voltage circuit SPRE, a second voltage circuit RPRE, a sampling circuit SAM, and an analog-to-digital converter ADC to output and sense a voltage through the first reference line VREF1.

[0062] The first voltage circuit SPRE and the second voltage circuit RPRE may perform a voltage output operation to initialize a node or circuit included in the subpixel SP, or charge the node or circuit to a specific voltage level. The first voltage circuit SPRE and the second voltage circuit RPRE may include a first reference voltage source VPRES and a second reference voltage source VPRER, respectively. The first voltage circuit SPRE may output a first reference voltage based on the first reference voltage source VPRES, and the second voltage circuit RPRE may output a second reference voltage based on the second reference voltage source VPRER. The first reference voltage may be set to a voltage lower than the second reference voltage.

[0063] The sampling circuit SAM may perform a sampling operation to acquire a sensing voltage through the first reference line VREF1. For example, the sampling circuit SAM may acquire a sensing voltage from a sensing capacitor PCAP formed on the first reference line VREF1 based on the sensing capacitor PCAP.

[0064] The analog-to-digital converter ADC can convert the analog sensing voltage acquired by the sampling circuit SAM into a digital sensing voltage and output the digital sensing voltage. For example, the analog-to-digital converter ADC can convert the analog sensing voltage charged in the sensing capacitor PCAP into a digital sensing voltage and output the digital sensing voltage.

[0065] The timing controller 120 may include a compensator that performs a compensation operation based on a sensing voltage (sensing data value) supplied from the sensing circuit 145. The compensator included in the timing controller 120 may determine whether the driving transistor DT or the organic light emitting diode OLED included in the subpixel SP has degraded based on the sensing voltage, and compensate for the degradation.

[0066] like Fig.11 As shown, according to the first example, the light emitting display device may perform a sequential sensing method in which sensing is performed from the first gate line GL1 to the M-th gate line GLm of the display panel 150. Fig.11 An example is shown in which sensing is sequentially performed starting from the first gate line GL1 which is the top of the display panel 150 , but sensing may start from the Mth gate line GLm which is the bottom of the display panel 150 .

[0067] like Fig.12 As shown, according to the second example, the light emitting display device may perform a random sensing method in which only the I-th gate line GLi of the display panel 150 is sensed. Fig.12 An example in which only the I-th gate line GLi, which is one of the specific gate lines, is sensed is shown, but the sensing target may be two or more gate lines.

[0068] Fig.13 is a diagram showing a virtual pixel group included in a display panel of a light emitting display device according to an embodiment, and Figures 14 to 16 is a diagram illustrating a track driving method of a display panel according to an embodiment.

[0069] like Fig.13 As shown, the display panel 150 according to the embodiment may include virtual pixel groups DPG1 to DPG4 set in the outer area (or frame area) of the display area. The virtual pixel groups DPG1 to DPG4 may include a first virtual pixel group DPG1, a second virtual pixel group DPG2, a third virtual pixel group DPG3 and a fourth virtual pixel group DPG4.

[0070] The first dummy pixel group DPG1 may be located in the left outer area of ​​the display panel 150. The second dummy pixel group DPG2 may be located in the right outer area of ​​the display panel 150. The third dummy pixel group DPG3 may be located in the upper outer area of ​​the display panel 150. The fourth dummy pixel group DPG4 may be located in the lower outer area of ​​the display panel 150.

[0071] The first virtual pixel group DPG1 may be connected to the first virtual data line DDL1 to the Jth virtual data line DDLj, and may include a plurality of virtual sub-pixels DP arranged in the vertical direction. Here, j may be an integer of 2 or more. Although not shown, the first virtual pixel group DPG1 may be connected to the virtual gate line to perform the same operation as the sub-pixels arranged in the display area of ​​the display panel 150. In addition, the second virtual pixel group DPG2 located in the outer area opposite to the first virtual pixel group DPG1 may also have the same structure as the first virtual pixel group DPG1.

[0072] The third virtual pixel group DPG3 may be connected to the first virtual gate line DGL1 to the Jth virtual gate line DGLj, and may include a plurality of virtual sub-pixels DP arranged in the horizontal direction. Here, j may be an integer of 2 or more. Although not shown, the third virtual pixel group DPG3 may be connected to the virtual data line to perform the same operation as the sub-pixels arranged in the display area of ​​the display panel 150. In addition, the fourth virtual pixel group DPG4 located in the outer area opposite to the third virtual pixel group DPG3 may also be arranged in the same form as the third virtual pixel group DPG3.

[0073] Also, note that Fig.13It is briefly shown that a virtual pixel group consisting of a plurality of virtual sub-pixels is set in each outer region of the display panel 150 according to an embodiment. In addition, since the virtual pixel groups DPG1 to DPG4 including a plurality of virtual sub-pixels are not actually driven, these virtual pixel groups can be implemented by significantly increasing the number of driving transistors compared to the sub-pixels included in the display region.

[0074] like Figures 14 to 16 As shown, the display panel 150 according to the embodiment can display a specific image (e.g., a screen saver image) instead of a general image. In this case, the position of the displayed image can be moved in the horizontal direction (X1→X2 or X1←X2), the vertical direction (Y2←Y1 or Y2→Y1), or the horizontal and vertical directions.

[0075] Fig.15 1 shows an example in which the position of the display image moves from Y2 to Y1 along the vertical direction of the display panel 150. Fig.15 As shown, when the position of the display image moves from the top to the bottom, the third virtual pixel group DPG3 located in the upper outer area of ​​the display panel 150 may display a black image BLK. In the opposite case, Fig.13 The fourth virtual pixel group DPG4 shown in FIG. 4 displays a black image.

[0076] Fig.16 An example is shown in which the position of the display image moves from X2 to X1 along the horizontal direction of the display panel 150. Fig.16 As shown, when the position of the display image moves from right to left, the second virtual pixel group DPG2 located in the right outer area of ​​the display panel 150 can display the black image BLK. In the opposite case, Fig.13 The first virtual pixel group DPG1 shown in FIG. 1 displays a black image.

[0077] When a specific image (hereinafter referred to as a protection image) is displayed as described above, if the position where the protection image is displayed is moved using the track driving method, the sub-pixels included in the display panel 150 continuously display the same image, so the degradation phenomenon can be delayed. In addition, if in addition to moving the position where the protection image is displayed, the virtual pixel group set in the outer area is displayed in black, the problem that the movement of the position of the protection image is visible on the screen can be prevented, or the brightness difference problem caused by the movement of the position of the protection image can be improved.

[0078] The light emitting display device according to the embodiment can use the virtual pixels (or virtual sub-pixels) included in the virtual pixel groups DPG1 to DPG4 to shorten the sensing voltage acquisition time. Hereinafter, a case where the position of the protection image displayed on the display panel 150 moves from the top to the bottom (eg, Fig.15 In addition, an example of shortening the sensing voltage acquisition time using a virtual sub-pixel will be described below.

[0079] Fig.17 is a diagram showing the position of a sensing target sub-pixel of a display panel according to an embodiment, Fig.18 yes Fig.17 An equivalent circuit diagram of the Cth virtual sub-pixel and the Kth sub-pixel shown; Fig.19 is shown for Fig.18 The driving waveform of the sub-pixel obtaining the sensing voltage is shown in FIG. Fig. 20 It is shown that Fig.18 A diagram showing the path for a sub-pixel to obtain a sensing voltage, and Fig.21 is a graph showing a difference between a sensing value of a Cth dummy sub-pixel and a sensing value of a Kth sub-pixel.

[0080] like Fig.17 As shown, when the position of the protection image moves from the top to the bottom, the third dummy pixel group DPG3 located in the upper outer area of ​​the display panel 150 may display the black image BLK.

[0081] In order to shorten the sensing voltage acquisition time, the light-emitting display device according to the embodiment may drive and sense at least one first sub-pixel disposed in the display area of ​​the display panel 150 and at least one first dummy sub-pixel disposed in the outer area of ​​the display panel 150. On the other hand, a conventional light-emitting display device specifies a sensing line where a sensing target is located, and drives and senses only one sub-pixel on the sensing line of the display panel 150.

[0082] For example, the light-emitting display device according to the embodiment can designate the Kth sub-pixel SPk of the display area as the first sensing target line SL1, designate the Cth virtual sub-pixel DPC of the upper outer area as the second sensing target line SL2, and drive and sense the Kth sub-pixel SPk and the Cth virtual sub-pixel DPC. Here, the Kth sub-pixel SPk is a specific sub-pixel in the display area, and the Cth virtual sub-pixel DPC is a specific virtual sub-pixel in the outer area. Hereinafter, the embodiment will be described based on the Kth sub-pixel SPk and the Cth virtual sub-pixel DPC.

[0083] like Fig.16 and Fig.18As shown, the Cth virtual sub-pixel DPC of the upper outer area and the Kth sub-pixel SPk of the display area can be implemented based on the same elements. The Cth virtual sub-pixel DPC and the Kth sub-pixel SPk can be connected to the same Jth data line DLj and the same Ith reference line VREFi. The Cth virtual sub-pixel DPC can be connected to the Cth virtual gate line DGLc, and the Kth sub-pixel SPk can be connected to the Kth gate line GLk.

[0084] Hereinafter, to describe an example of simultaneously driving and sensing the C th dummy subpixel DPc and the K th subpixel SPk, the scanning signal and the sensing signal applied to the K th gate line GLk and the scanning signal and the sensing signal applied to the C th dummy gate line DGLc are not distinguished from each other. For example, the K th gate line GLk and the C th dummy gate line DGLc may synchronously receive the same type of scanning signal and sensing signal at the same time.

[0085] like Fig.19 As shown, the light emitting display device according to the embodiment may operate in the first period P1, the second period P2, the third period P3, and the fourth period P4 in order to shorten the sensing voltage acquisition time.

[0086] like Fig.10 as well as Figures 17 to 20 As shown, during the first period P1, the first reference voltage may be applied to the I reference line VREFi of the Cth virtual subpixel DPc and the Kth subpixel SPk. During the first period P1, the first voltage circuit SPRE including the first reference voltage source VPRES may be turned on in response to the first voltage circuit control signal VpreS at a high voltage.

[0087] The first voltage circuit control signal VpreS may be applied as a high voltage during the first period P1 and then changed to a low voltage. During the first period P1, sensing nodes of the driving transistors DT included in the Cth dummy subpixel DPc and the Kth subpixel SPk may be initialized by the first reference voltage.

[0088] like Fig.10 as well as Figures 17 to 20 As shown, during the second period P2, the sensing data voltage Sdata may be applied to the J data line DLj of the C th dummy subpixel DPc and the K th subpixel SPk. During the second period P2, the driving transistor DT of the C th dummy gate line DGLc and the K th gate line GLk may operate as a constant current source for a certain period of time.

[0089] During the first period P1 and the second period P2, the first scan signal and the first sensing signal Scan&Sense at a high voltage may be applied to the first scan line Gate1 and the second scan line Gate2 of the C th virtual gate line DGLc and the K th gate line GLk. The switching transistor SW and the sensing transistor ST included in the C th virtual sub-pixel DPc and the K th sub-pixel SPk may be turned on by the first scan signal and the first sensing signal Scan&Sense at a high voltage. The first scan signal and the first sensing signal Scan&Sense may be applied as a high voltage during the first period P1 and the second period P2, and then changed to a low voltage during the third period P3 and the fourth period P4.

[0090] like Fig.10 as well as Figures 17 to 20 As shown, during the third period P3, the Cth dummy subpixel DPc and the Kth subpixel SPk are electrically floated, and then, a gradual voltage increase may occur at the sensing node due to the sensing data voltage Sdata applied to the driving transistor DT.

[0091] Fig.19 The following example is shown: the voltage increase occurs at a higher slope in the Cth virtual sub-pixel DPc than in the Kth sub-pixel SPk. This is because the voltage change at the sensing node of the driving transistor DT is proportional to the current flowing through the driving transistor DT. Therefore, Fig.19 It may be interpreted as showing that due to different driving conditions (eg, degradation degrees) of the Cth dummy subpixel DPc and the Kth subpixel SPk, the Cth dummy subpixel DPc and the Kth subpixel SPk may have different voltage increase rates.

[0092] like Fig.10 as well as Figures 17 to 20 As shown, during the fourth period P4, the sampling circuit SAM connected to the I reference line VREFi of the C th dummy sub-pixel DPC and the K th sub-pixel SPk may be turned on in response to the sampling control signal Sam.

[0093] During the fourth period P4, the sensing circuit 145 can obtain the sensing voltage Vsen applied to the sensing nodes of the Cth virtual sub-pixel DPC and the Kth sub-pixel SPk based on the sampling circuit SAM. Here, the first sensing value a applied to the sensing node of the Kth sub-pixel SPk and the second sensing value b applied to the sensing node of the Cth virtual sub-pixel DPC are summed, and thus the sampling circuit SAM can obtain a third sensing value c corresponding to a+b as the sensing voltage Vsen.

[0094] The light-emitting display device according to the embodiment can detect the characteristics of the driving transistor DT included in the Cth virtual sub-pixel DPC and the Kth sub-pixel SPk (by which the presence or absence of degraded values ​​can be determined), and update the compensation value. The second sensing value b applied to the sensing node of the Cth virtual sub-pixel DPC can correspond to a virtual value for shortening the sensing voltage acquisition time. Therefore, since the second sensing value applied to the Cth virtual sub-pixel DPC is used to act as a constant current source that increases the current when sensing the Kth sub-pixel SPk, the second sensing value b corresponding to the virtual value obtained from the Cth virtual sub-pixel DPC can be removed by an algorithm in the timing controller (the second sensing value b is offset).

[0095] Meanwhile, the Kth subpixel SPk displays an image with a certain brightness in the display area and is therefore susceptible to degradation, while the Cth dummy subpixel DPc displays a black image (or does not display an image) in the outer area and is therefore less susceptible to degradation than the Kth subpixel SPk. Fig.21 As shown, the first sensing value a applied to the sensing node of the Kth sub-pixel SPk may be variable, and the second sensing value b applied to the sensing node of the Cth dummy sub-pixel DPc may be constant.

[0096] For example, virtual sub-pixels along the outer border of the display area can be saved or retained (e.g., protected) so that the virtual sub-pixels can be used as a constant reference for evaluating degradation of conventionally driven sub-pixels. In addition, because the virtual sub-pixels and conventional sub-pixels are sensed together at the same time, this can speed up or shorten the sensing time because reliable measurements can be obtained at an earlier point in time. In other words, the component resulting from the sensing of the virtual sub-pixels can act as a reliable bias that can be added to the sensing of the conventional sub-pixels to shorten the measurement time, and because it can be known and constant, the bias can be removed (offset) later.

[0097] In other words, it can be assumed that the second sensing value b applied to the sensing node of the Cth virtual subpixel (DPc) is constant. The timing controller can implement the modeling expression based on the above logic, and remove the second sensing value b corresponding to the virtual value (shift the second sensing value b) based on the modeling expression.

[0098] The timing controller may calculate a compensation value for compensating for degradation of the driving transistor DT included in the Kth subpixel SPk based on the sensing voltage obtained from the Kth subpixel SPk. In addition, the timing controller may calculate a compensation value for compensating for subpixels disposed in the display area of ​​the display panel 150 by using the sensing voltage obtained from the Kth subpixel SPk as a representative value. In addition, the timing controller may calculate a compensation value associated with a temperature change (temperature distribution) in the display panel 150.

[0099] An example in which the Cth virtual sub-pixel DPC and the Kth sub-pixel SPk are connected to the same data line and the same reference line is shown and described above. However, the Cth virtual sub-pixel DPC and the Kth sub-pixel SPk may be connected to different data lines and reference lines, and the sensing voltages obtained from the Cth virtual sub-pixel DPC and the Kth sub-pixel SPk may be summed in the sensing circuit 145.

[0100] Fig. 22 and Fig.23 is a diagram showing advantages of a sensing voltage acquisition method according to an embodiment, and Fig.24 is a diagram illustrating a driving environment to which a sensing voltage acquisition method according to an embodiment may be applied.

[0101] like Fig. 22 As shown, in the conventional sensing voltage acquisition method, only one sub-pixel is driven and sensed, so the sensing voltage Vsen-1 can be acquired according to the sampling control signal Sam generated at the first time t1. On the other hand, in the present embodiment, the sub-pixel used for image display and the virtual sub-pixel not used for image display are driven and sensed together, so the sensing voltage Vsen-2 can be acquired according to the sampling control signal Sam generated at the second time t2 earlier than the first time t1. That is, compared with the conventional sensing voltage acquisition method, the sensing voltage acquisition method according to the present embodiment can shorten the sensing voltage acquisition time. For example, the sensing of the virtual sub-pixel can act as a reliable bias to accelerate the sensing voltage acquisition time.

[0102] like Fig.23 As shown, the sensing voltage acquisition method according to the embodiment can drive and sense multiple virtual sub-pixels or multiple pixels that are not used for image display. Therefore, the sensing voltage acquisition method according to the embodiment can shorten the time required to acquire the sensing voltage Vsen by Δt, which corresponds to the number of virtual sensing targets Vsen1 to Vsenj.

[0103] like Fig.24 As shown, the sensing voltage acquisition method according to the embodiment can be performed during the blank period BLK included in the vertical synchronization signal Vsync. That is, the blank period BLK can be shortened or extended according to factors determining the driving frequency, such as the vertical synchronization signal Vsync.

[0104] For example, the blank period BLK of the vertical synchronization signal Vsync generated based on a driving frequency of 60Hz is longer than the blank period BLK of the vertical synchronization signal Vsync generated based on a driving frequency of 240Hz. In other words, when the driving frequency of the light-emitting display device is 240Hz, the time for acquiring the sensing voltage is shorter than the time for acquiring the sensing voltage when the driving frequency is 60Hz. Therefore, the sensing voltage acquisition method according to the embodiment may be advantageous when applied to a light-emitting display device with a high driving frequency (e.g., a high-resolution, high-frequency, high-PPI model). In other words, by adding the bias provided by sensing both the virtual sub-pixel and the conventional sub-pixel together, a reliable measurement can be obtained faster, and a reliable measurement can be performed during a shorter blank period BLK (e.g., BLK when driven at 240Hz).

[0105] Fig.25 is a flowchart showing a sensing voltage acquisition method according to a first example, and Fig.26 is a flowchart illustrating a sensing voltage acquisition method according to a second example.

[0106] like Fig.25 As shown, according to the first example, an input value (e.g., resolution or frequency) is analyzed (S110), it is determined whether the input value is different from a reference value (S120), and if the input value is the same as the reference value (N), the sub-pixels SP set in the display area are mainly sensed and compensation is performed (S150).

[0107] On the other hand, if the input value is different from the reference value (Y), it is determined whether the track driving is being performed (S130), and if the track driving is being performed (Y), the sub-pixel SP set in the display area and the virtual sub-pixel DP set in the external area are sensed together, and compensation is performed (S140). On the other hand, if the track driving is not performed (N), the sub-pixel SP set in the display area is mainly sensed, and compensation is performed (S150).

[0108] As in Fig.25 As can be determined in the example, when one of the resolution and the frequency is high and during track driving, the sensing voltage acquisition method according to the embodiment (eg, combining the sensing of the virtual sub-pixel and the regular sub-pixel together) can be performed.

[0109] like Fig.26 As shown, according to the second example, it is determined whether the track driving is being performed (S210), and if the track driving is not being performed (N), the sub-pixels SP provided in the display area are mainly sensed and compensation is performed (S220).

[0110] On the other hand, if track driving (Y) is being performed, the input value (e.g., resolution or frequency) is analyzed (S230), it is determined whether the input value is equal to a first reference value (S240), and if the input value is equal to the first reference value (Y), the sub-pixel SP set in the display area and the virtual sub-pixel DP displayed in the external area are sensed together under the first condition and compensation is performed (S250).

[0111] If the input value is not equal to the first reference value (N), it is determined whether the input value is equal to the second reference value (S260), and if the input value is equal to the second reference value (Y), the sub-pixel SP set in the display area and the virtual sub-pixel DP set in the external area are sensed together under the second condition and compensation is performed (S270).

[0112] If the input value is not equal to the second reference value (N), the subpixel SP disposed in the display area and the dummy subpixel DP disposed in the outer area are sensed together under a third condition and compensation is performed ( S280 ).

[0113] As in Fig.26 As can be determined in the example, the sensing voltage acquisition method according to the embodiment can configure multiple conditional expressions taking into account the diversity of resolution and frequency, and change the number of virtual sub-pixels DP or the number of virtual pixels included in the condition according to the resolution and frequency.

[0114] As described above, the present disclosure has the following effects: reducing the time required to obtain the sensing voltage, so that the degradation of the elements included in the display panel can be sensed and compensated even in high-resolution, high-frequency and high-PPI models, and ensuring the time required for accurate compensation based on the minimization of the sensing time to improve the compensation performance.

[0115] It will be apparent to those skilled in the art that various modifications and variations may be made in the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to cover modifications and variations of the present disclosure as long as they are within the scope of the appended claims and their equivalents.

Claims

1. A display device, comprising: A display panel, the display panel comprising sub-pixels arranged in a display area and dummy sub-pixels arranged in an external area; a driving circuit configured to output a sensing data voltage for sensing a first sub-pixel among the sub-pixels and a first dummy sub-pixel among the dummy sub-pixels; as well as A sensing circuit is configured to obtain a third sensing value as a sensing voltage, the third sensing value being obtained by adding a first sensing value applied to a sensing node of the first sub-pixel and a second sensing value applied to a sensing node of the first dummy sub-pixel.

2. The display device according to claim 1, wherein: The second sensing value applied to the first dummy sub-pixel serves as a constant current source for increasing current when the first sensing value applied to the sensing node of the first sub-pixel is sensed. 3 . The display device according to claim 1 , further comprising a compensator configured to generate a compensation value for compensating the first subpixel based on the first sensing value excluding the second sensing value from the sensing voltage.

4. The display device according to claim 1, wherein: The sensing circuit acquires a sensing value from one of the virtual sub-pixels or acquires sensing values ​​from a plurality of virtual sub-pixels in response to at least one of a resolution, a frequency, or pixels per inch of the display panel.

5. The display device according to claim 1, wherein: When the position where the protection image displayed based on the sub-pixel is displayed is moved, the virtual sub-pixel displays a black image.

6. The display device according to claim 3, wherein: The compensator is further configured to generate a compensation value for compensating a sub-pixel in a display area based on the first sensing value.

7. A display device, comprising: A display panel, the display panel comprising sub-pixels arranged in a display area and dummy sub-pixels arranged in an external area; a driving circuit configured to: display a protection image based on the sub-pixels, move a display position at which the protection image is displayed, and move a position of a black image displayed on at least one of the virtual sub-pixels whenever the display position of the protection image is moved; as well as A sensing circuit is configured to obtain a first sensing value from a first sub-pixel among the sub-pixels, obtain a second sensing value from a first virtual sub-pixel displaying a black image among the virtual sub-pixels, and obtain a third sensing value as a sensing voltage, wherein the third sensing value is obtained by adding the first sensing value to the second sensing value. 8 . The display device of claim 7 , further comprising a compensator configured to generate a compensation value for compensating the first subpixel based on the first sensing value excluding the second sensing value from the sensing voltage.

9. The display device according to claim 7, wherein: The sensing circuit acquires a sensing value from one of the virtual sub-pixels or acquires sensing values ​​from a plurality of virtual sub-pixels in response to at least one of a resolution, a frequency, or pixels per inch of the display panel.

10. The display device according to claim 8, wherein: The compensator is further configured to generate a compensation value for compensating a sub-pixel in a display area based on the first sensing value.

11. A method for driving a display device, comprising: displaying a protection image based on sub-pixels provided in a display area of ​​a display panel of the display device, and moving a display position at which the protection image is displayed; displaying a black image on at least one of the virtual sub-pixels disposed in the outer area of ​​the display panel, and causing the position of the black image to move whenever the display position of the protection image is moved; Acquire a first sensing value from a first sub-pixel among the sub-pixels, acquire a second sensing value from a first virtual sub-pixel among the virtual sub-pixels that displays the black image, and acquire a third sensing value as a sensing voltage, the third sensing value being obtained by adding the first sensing value to the second sensing value; as well as A compensation value for compensating at least one of the sub-pixels is generated based on the first sensing value excluding the second sensing value from the sensing voltage.

12. The method according to claim 11, wherein: Acquiring the sensing voltage includes acquiring a sensing value from one of the virtual sub-pixels or acquiring sensing values ​​from a plurality of virtual sub-pixels in response to at least one of a resolution, a frequency, or pixels per inch of the display panel.

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