KR102565240B1 - Display device and method for controlling thereof - Google Patents

Abstract

The present invention relates to a display device and a control method of the display device. A display device according to an exemplary embodiment of the present invention includes a display panel having a plurality of subpixels, a data driver supplying data signals to a plurality of data lines disposed on the display panel, and a plurality of gates disposed on the display panel. A gate driver supplying a gate signal to a line, and determining a recovery voltage value supplied to the subpixel when the subpixel operates in the sensing mode, based on a reference voltage value applied when the subpixel operates in the driving mode. It includes a compensation part that According to the present invention, when the display panel is switched from a sensing mode to a driving mode, a phenomenon in which a reference voltage becomes unstable due to coupling with a data voltage is prevented, thereby preventing bright or dark lines from occurring in the display panel.

Description

Display device and method for controlling the display device {DISPLAY DEVICE AND METHOD FOR CONTROLLING THEREOF}

The present invention relates to a display device and a control method of the display device.

An Organic Light Emitting Diode (OLED) display device is a display device using OLED, a self-luminous element that emits light through an organic light emitting layer by recombination of electrons and holes. It is in the limelight as a display device.

Each of the plurality of subpixels constituting the OLED display device includes an OLED composed of an anode electrode, a cathode electrode, and an organic light emitting layer therebetween, and a subpixel driving circuit that independently drives the OLED. The sub-pixel driving circuit includes a switching thin film transistor (TFT), a driving TFT, and a capacitor. The switching TFT charges the capacitor with a voltage corresponding to the data signal in response to the scan pulse, and the driving TFT controls the amount of current supplied to the OLED according to the magnitude of the voltage charged in the capacitor to adjust the amount of light emitted by the OLED.

In such an OLED display device, circuit elements such as an organic light emitting diode (OLED) or a driving transistor included in each sub-pixel each have a unique characteristic value (eg, threshold voltage, mobility, etc.). Such a circuit element is degraded according to the driving time of the OLED display device, and the characteristic value of each circuit element is changed due to the deterioration. Changes in the characteristic values of the circuit elements cause luminance deviations between subpixels including the circuit elements, thereby degrading overall luminance uniformity of the display panel.

In order to solve this problem, a technique of sensing a characteristic value of a circuit element included in each sub-pixel and performing compensation for the characteristic value of the circuit element based on the sensed value has been applied.

Each sub-pixel of the OLED display device to which the compensation technology is applied is operated in a sensing mode and a driving mode. In the sensing mode, a sensing voltage for sensing a characteristic value is supplied to each sub-pixel, and in a driving mode, a data voltage for displaying image data is supplied to each sub-pixel.

According to the prior art, a recovery voltage for shortening the charging time of the data voltage is supplied before switching from the sensing mode to the driving mode. However, when a data voltage is supplied to each subpixel in a driving mode after supplying a recovery voltage, a phenomenon in which the reference voltage becomes unstable due to coupling between the data voltage and the reference voltage occurs. As such, when the reference voltage becomes unstable in the driving mode, a phenomenon in which a bright line or a dark line appears on a specific line when an image is displayed on the display panel occurs.

The present invention provides a display device and a display device capable of preventing occurrence of bright or dark lines in a display panel by preventing a reference voltage from being unstable due to coupling with a data voltage when the display panel is switched from a sensing mode to a driving mode. It aims to provide a control method.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned above can be understood by the following description and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations indicated in the claims.

A display device according to an exemplary embodiment of the present invention includes a display panel having a plurality of subpixels, a data driver supplying data signals to a plurality of data lines disposed on the display panel, and a plurality of gates disposed on the display panel. A gate driver supplying a gate signal to a line, and determining a recovery voltage value supplied to the subpixel when the subpixel operates in the sensing mode, based on a reference voltage value applied when the subpixel operates in the driving mode. It includes a compensation part that

In one embodiment of the present invention, the compensation unit adjusts the recovery voltage value when the size of the reference voltage value is out of a predetermined limit range.

Also, in one embodiment of the present invention, the compensation unit adjusts the recovery voltage value based on a difference value between the reference voltage value and a previously set recovery voltage value.

Also, in one embodiment of the present invention, the compensation unit maintains the recovery voltage value as a previously set recovery voltage value when the reference voltage value is included in a predetermined limit range.

Also, in one embodiment of the present invention, the compensation unit determines the reference voltage value based on the characteristic value of the driving transistor of the sub-pixel sensed in the sensing mode.

In addition, a control method of a display device according to an embodiment of the present invention includes the steps of driving a subpixel in a sensing mode and sensing a characteristic value of a driving transistor of the subpixel, a reference applied when the subpixel operates in the driving mode. Comparing a voltage value with a predetermined limit range, determining a recovery voltage value supplied to the sub-pixel according to the comparison result, and supplying a data voltage according to the determined recovery voltage value to the sub-pixel. .

In one embodiment of the present invention, the determining of the recovery voltage value includes adjusting the recovery voltage value when the magnitude of the reference voltage value is out of a predetermined limit range.

In one embodiment of the present invention, the determining of the recovery voltage value includes adjusting the recovery voltage value based on a difference between the reference voltage value and a previously set recovery voltage value.

In one embodiment of the present invention, the determining of the recovery voltage value includes maintaining the recovery voltage value as a previously set recovery voltage value when the reference voltage value is within a predetermined limit range.

The control method of the display device according to an exemplary embodiment of the present invention further includes determining the reference voltage value based on the characteristic value.

According to the present invention, when the display panel is switched from a sensing mode to a driving mode, a phenomenon in which a reference voltage becomes unstable due to coupling with a data voltage is prevented, thereby preventing bright or dark lines from occurring in the display panel.

1 shows the configuration of a display device.
2 is a circuit diagram of a subpixel included in a display device.
3 is a timing diagram illustrating timing at which a vertical sync signal and a data voltage are applied.
FIG. 4 is a diagram illustrating a change in magnitude of a voltage applied through a data line in a sensing mode and a driving mode of a subpixel according to the prior art.
5 is a configuration diagram of a display device according to an exemplary embodiment of the present invention.
6 is a diagram for explaining dispersion compensation according to sensing characteristic values of a display device according to an exemplary embodiment of the present invention.
7 is a diagram for describing time-lapse compensation according to sensing characteristic values of a display device according to an exemplary embodiment of the present invention.
8 is a diagram illustrating a change in magnitude of a voltage applied through a data line in a sensing mode and a driving mode of a subpixel according to an embodiment of the present invention.
9 is a flowchart of a control method of a display device according to an embodiment of the present invention.

The above objects, features and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will be able to easily implement the technical spirit of the present invention. In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

1 shows the configuration of a display device.

Referring to FIG. 1 , the display device 1 includes a display panel 110 . The display panel 110 includes a plurality of data lines DL, a plurality of first gate lines SL1 and a plurality of second gate lines SL2. The plurality of data lines DL and the plurality of first and second gate lines SL1 and SL2 cross each other to define a sub-pixel area. A subpixel SP is disposed in each subpixel area, and a high potential driving voltage ELVDD, a low potential driving voltage VSS, and a reference voltage Vref are commonly supplied to the pixels SP.

When a specific gate line is opened, the data driver 12 converts the image data RGB received from the timing controller 10 into an analog data voltage and supplies it to a plurality of data lines DL. The data driver 12 operates based on the data control signal DCS provided from the timing controller 10 .

The data driver 12 may include at least one source driver integrated circuit. Each source driver integrated circuit is connected to a bonding pad of the display panel 110 using a tape automated bonding (TAB) method or a chip on glass (COG) method, or It may be directly disposed on 110 or may be integrated and disposed on display panel 110 .

In addition, each source driver integrated circuit may be implemented in a Chip On Film (COF) method. In this case, one end of each source driver integrated circuit is bonded to at least one source printed circuit board, and the other end is bonded to the display panel 110 .

The first gate driver 14 generates a first scan signal and sequentially supplies it to the plurality of first gate lines SL1. The first gate driver 14 operates based on the first gate control signal GCS1 provided from the timing controller 10 .

The second gate driver 16 generates a second scan signal and sequentially supplies it to the plurality of second gate lines SL2. The second gate driver 16 operates based on the second gate control signal GCS2 provided from the timing controller 10 .

The gate drivers 14 and 16 may include one or more gate driver integrated circuits. Each gate driver integrated circuit is connected to a bonding pad of the organic light emitting display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, or by a GIP method. It can be implemented as a (Gate In Panel) type and directly disposed on the display panel 110 . In addition, the gate drivers 14 and 16 may be integrated and disposed on the display panel 110, or may be implemented in a chip on film (COF) method mounted on a film connected to the display panel 110. .

The timing controller 10 aligns the image data RGB input from the source unit 120 according to the size and resolution of the display panel 110 and supplies it to the data driver 12 . The timing controller 10 uses synchronization signals input from the outside, such as a dot clock (DCLK), a data enable signal (DE), a horizontal synchronization signal (Hsync), and a vertical synchronization signal (Vsync), to provide a data control signal ( DCS) and first and second gate control signals GCS1 and GCS2 are generated, and the generated data control signal DCS and the first and second gate control signals GCS1 and GCS2 are transferred to the data driver 12 and the It is supplied to the first and second gate drivers 14 and 16, respectively.

The timing control unit 10 is a source printed circuit board to which the source driver integrated circuit is bonded and a control printed circuit board connected through a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (FPC). (Control Printed Circuit Board).

Each sub-pixel SP disposed on the display panel 110 may include a circuit element such as a transistor. For example, each sub-pixel SP may include an organic light emitting diode (OLED) and a circuit element such as a driving transistor (DRT) for driving the organic light emitting diode (OLED). The type and number of circuit elements constituting each sub-pixel SP may be variously determined according to functions and design methods.

2 is a circuit diagram of a subpixel included in a display device.

Referring to FIG. 2 , each sub-pixel SP includes an organic light emitting diode OLED, a driving transistor DRT driving the organic light emitting diode OLED, a first node N1 of the driving transistor DRT and a reference voltage. A sensing transistor (SENT: Sensing Transistor) electrically connected between a reference voltage line (RVL: Reference Voltage Line) supplying (Vref: Reference Voltage), the second node (N2) of the driving transistor (DRT) and the data voltage ( A switching transistor (SWT) electrically connected between the data line (DL) supplying Vdata) and electrically connected between the first node (N1) and the second node (N2) of the driving transistor (DRT) It is composed of a storage capacitor (Cstg: Storage Capacitor) and the like.

An organic light emitting diode (OLED) may include a first electrode (eg, an anode electrode or a cathode electrode), an organic layer, and a second electrode (eg, a cathode electrode or an anode electrode).

The driving transistor DRT drives the organic light emitting diode OLED by supplying a driving current to the organic light emitting diode OLED. The first node N1 of the driving transistor DRT may be electrically connected to the first electrode of the organic light emitting diode OLED and may be a source node or a drain node. The second node N2 of the driving transistor DRT may be electrically connected to a source node or a drain node of the switching transistor SWT and may be a gate node. The third node N3 of the driving transistor DRT may be electrically connected to a driving voltage line (DVL) that supplies the driving voltage EVDD, and may be a drain node or a source node.

The sensing transistor SENT is turned on by the gate signal and applies the reference voltage Vref to the first node N1 of the driving transistor DRT. Also, when the sensing transistor SENT is turned on, it may be used as a voltage sensing path for the first node N1 of the driving transistor DRT.

When the switching transistor SWT is turned on by the gate signal, the data voltage Vdata supplied through the data line DL is transferred to the second node N2 of the driving transistor DRT.

In this case, the sensing transistor SENT and the switching transistor SWT may be connected to different gate lines GL to be separately controlled on-off or connected to the same gate line GL to be controlled.

The storage capacitor Cstg is electrically connected between the first node N1 and the second node N2 of the driving transistor DRT, and maintains a data voltage Vdata corresponding to an image signal or a voltage corresponding thereto. .

Meanwhile, as the driving time of each sub-pixel SP increases as described above, degradation of circuit elements such as the organic light emitting diode (OLED) and the driving transistor (DRT) may progress. Accordingly, unique characteristic values (eg, threshold voltage, mobility, etc.) of circuit elements such as organic light emitting diodes (OLEDs) and driving transistors (DRTs) may change.

The change in the characteristic value of the circuit element causes a change in the luminance of the corresponding sub-pixel SP, and the difference in the change in the characteristic value between the circuit elements due to the difference in the degree of deterioration between the circuit elements causes a luminance deviation between the sub-pixels SP and the display panel ( 110) may cause a decrease in luminance uniformity.

Here, the characteristic value of the circuit element includes the threshold voltage or mobility of the driving transistor DRT, and may also include the threshold voltage of the organic light emitting diode OLED.

The display device 1 provides a sensing function for sensing a characteristic value variation between subpixels SP or a characteristic value deviation between each subpixel SP, and a compensation function for compensating for a characteristic value of the subpixel SP using a sensing result. can do.

When the display device 1 is driven in the sensing mode, a sensing voltage is applied to each sub-pixel SP to sense a characteristic value of each sub-pixel SP, and compensation data is generated by reflecting the sensed characteristic value.

When the display device 1 is driven in the driving mode, a data voltage reflecting compensation data generated through the sensing mode is applied to each sub-pixel SP, and an image is output through the display panel 10 .

3 is a timing diagram illustrating timing at which a vertical sync signal and a data voltage are applied.

As described above, while the image is driven through the display panel 10 , sensing may be performed to compensate for a characteristic value change between subpixels SP or a characteristic value deviation between each subpixel SP. Such sensing may be performed for each blank time Vblank between the active times Vactive based on the vertical synchronization signal Vsync.

During each active time (Vactive), data voltages (N-1 Frame Data, N Frame Data) corresponding to each frame of an image to be displayed through each sub-pixel (SP) are applied through the data line (DL). In each blank time Vblank, sensing is performed through application of sensing data.

More specifically, during the sensing data application period S1 in the blank time Vblank, a sensing voltage for sensing is applied through the data line DL. In the sensing period (Sensing), sensing is performed using the sensing voltage applied to the sensing data application period (S1). When sensing through the sensing period (Sensing) is completed, during the recovery period (S2), the recovery voltage for accelerating the charging speed of the data voltage (N Frame Data) to be applied in the next active time (Vacitve) is applied to the data line (DL). is authorized through

FIG. 4 is a diagram illustrating a change in magnitude of a voltage applied through a data line in a sensing mode and a driving mode of a subpixel according to the prior art.

As described above, the sensing mode of the sub-pixel (SP) determines the charging speed of the data voltage (N Frame Data) to be applied in the sensing period (Sensing) in which sensing is performed using the application of the sensing voltage and the next active time (Vacitve). A recovery period S2 in which a recovery voltage for speeding up is applied through the data line DL is included. According to the prior art, in the recovery period S2, the recovery voltage GRAY2 having a predetermined size is applied to the sub-pixel SP through the data line DL.

When the recovery period S2 elapses, the sub-pixel SP operates in a driving mode for displaying an image. During the driving mode operation, the data voltage Vdata corresponding to the image to be displayed is applied to the subpixel SP through the data line DL. Also, during the driving mode operation, the reference voltage Vref for driving the subpixel SP is applied to the subpixel SP through the reference voltage line RVL.

However, according to the prior art, when the sub-pixel SP operates in the driving mode, the reference voltage Vref is changed in the process of changing the voltage supplied through the data line DL from the recovery voltage GRAY2 to the data voltage Vdata. A phenomenon coupled with the data voltage Vdata occurs. Accordingly, as shown in FIG. 4 , a phenomenon in which the reference voltage Vref temporarily overshoots or undershoots and then stabilizes occurs. Due to such a change in the reference voltage Vref, each sub-pixel SP temporarily darkens or brightens, and this phenomenon is recognized as a bright line or a dark line of a specific line on the display panel 110 .

The coupling phenomenon of the reference voltage Vref to the data voltage Vdata and the resulting temporary change in the reference voltage Vref increase as the difference ΔV between the recovery voltage GRAY2 and the data voltage Vdata increases. appear.

In the present invention, overshooting or undershooting of the reference voltage Vref due to the coupling of the reference voltage Vref is improved by adjusting the difference ΔV between the recovery voltage GRAY2 and the data voltage Vdata. A phenomenon in which a bright line or a dark line of a specific line appears on the panel 110 is prevented.

5 is a configuration diagram of a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 5 , the display device according to an exemplary embodiment includes a sensing unit 310, a compensation unit 320, a memory 330, a reference voltage switch SPRE, and a sampling switch SAMP.

The sensing unit 310 senses a voltage for sensing a characteristic value or change thereof of the sub-pixel SP, converts the sensed voltage into a digital value, and outputs sensing data including the converted sensing value. Here, the characteristic value of the sub-pixel SP means the threshold voltage and mobility of the driving transistor DRT or the threshold voltage of the organic light emitting diode OLED.

The sensing unit 310 may be implemented by including at least one analog to digital converter (ADC). Each analog-to-digital converter (ADC) may be included inside the source driver integrated circuit, and may be disposed outside the source driver integrated circuit in some cases.

The compensating unit 320 performs a compensation process of compensating for characteristic value deviations between the sub-pixels SP by recognizing characteristic values or variations thereof using sensing data output from the sensing unit 310 . The compensator 320 may be included inside the timing controller 140 or may be disposed outside the timing controller 140 in some cases.

The memory 330 stores sensing data output by the sensing unit 310 and may store a compensation value calculated by the compensating unit 320 based on the sensing data.

The reference voltage switch SPRE controls whether or not to supply the reference voltage Vref to the reference voltage line RVL, and the sampling switch SAMP controls the voltage for sensing the characteristic value of the sub-pixel SP. A connection between the voltage line RVL and the sensing unit 310 is controlled.

When the reference voltage switch SPRE is turned on, the reference voltage Vref is supplied to the reference voltage line RVL. The reference voltage Vref supplied to the reference voltage line RVL may be applied to the first node N1 of the driving transistor DRT through the turned-on sensing transistor SENT.

Meanwhile, when the voltage of the first node N1 of the driving transistor DRT becomes a voltage state reflecting the characteristic value of the subpixel SP, a reference that may be equipotential with the first node N1 of the driving transistor DRT. The voltage of the voltage line RVL may also be in a voltage state reflecting the characteristic value of the sub-pixel SP. At this time, a voltage reflecting the characteristic value of the subpixel SP may be charged in the line capacitor formed on the reference voltage line RVL.

That is, when the sensing transistor SENT is turned on, the voltage of the first node N1 of the driving transistor DRT is charged to the voltage of the reference voltage line RVL or the line capacitor formed on the reference voltage line RVL. may be equal to the applied voltage.

When the voltage of the first node N1 of the driving transistor DRT becomes a voltage state reflecting the characteristic value of the subpixel SP, the sampling switch SAMP is turned on and the sensing unit 310 and the reference voltage line RVL are turned on. ) can be connected.

Accordingly, the sensing unit 310 senses the voltage of the reference voltage line RVL, which is a voltage state reflecting the characteristic value of the sub-pixel SP. In this case, the reference voltage line RVL may be referred to as a sensing line SL.

The sensing unit 310 senses the voltage of the first node N1 of the driving transistor DRT. In the case of sensing the threshold voltage of the driving transistor DRT, the voltage sensed by the sensing unit 310 may be a voltage value including the threshold voltage Vth or a change in the threshold voltage ΔVth of the driving transistor DRT.

In addition, in the case of sensing the mobility of the driving transistor DRT, the voltage sensed by the sensing unit 310 may be a voltage value for sensing the mobility of the driving transistor DRT.

Also, the voltage sensed by the sensing unit 310 may be a voltage value reflecting a threshold voltage, which is a characteristic value of the organic light emitting diode (OLED).

A compensation process by the sensing unit 310 and the compensating unit 320 when the display device operates in the sensing mode will be described below. First, a process of sensing the threshold voltage of the driving transistor DRT will be described. When the driving transistor DRT senses the threshold voltage, the first node N1 and the second node N2 of the driving transistor DRT are connected to the reference voltage, respectively. (Vref) and the sensing data voltage (Vdata).

Then, when the reference voltage switch SPRE is turned off, the first node N1 of the driving transistor DRT is floated. Accordingly, the voltage of the first node N1 of the driving transistor DRT rises.

The voltage of the first node N1 of the driving transistor DRT rises, then gradually decreases and becomes saturated. The saturated voltage of the first node N1 of the driving transistor DRT may correspond to a difference between the data voltage Vdata and the threshold voltage Vth or a difference between the data voltage Vdata and the threshold voltage deviation ΔVth. .

When the voltage of the first node N1 of the driving transistor DRT is saturated, the sensing unit 310 senses the saturated voltage of the first node N1 of the driving transistor DRT. The voltage Vsen sensed by the sensing unit 310 is a voltage (Vdata-Vth) obtained by subtracting the threshold voltage (Vth) from the data voltage (Vdata) or obtained by subtracting the threshold voltage deviation (ΔVth) from the data voltage (Vdata). It may be a voltage (Vdata-ΔVth).

Next, a method of sensing the mobility of the driving transistor DRT will be described. When the driving transistor DRT is driven for sensing the mobility, the first node N1 and the second node N2 of the driving transistor DRT are initialized with the reference voltage Vref and the sensing data voltage Vdata, respectively.

Then, when the reference voltage switch SPRE is turned off, the first node N1 of the driving transistor DRT is floated. At this time, the switching transistor SWT is turned off and the second node N2 of the driving transistor DRT is also floated. Accordingly, the voltage of the first node N1 of the driving transistor DRT starts to rise.

Here, the voltage increasing width ΔV of the first node N1 of the driving transistor DRT is a voltage increasing speed and varies depending on the current capability of the driving transistor DRT, that is, the mobility. That is, as the current capability (mobility) of the driving transistor DRT increases, the voltage at the first node N1 of the driving transistor DRT rises more steeply, and the voltage at the first node N1 of the driving transistor DRT increases for a certain period of time. ) has a large voltage rise (ΔV).

After the voltage of the first node N1 of the driving transistor DRT rises for a predetermined time, the sensing unit 310 senses the increased voltage of the first node N1 of the driving transistor DRT. A rate of change per time, that is, a slope, of the voltage rise ΔV according to the voltage Vsen sensed by the sensing unit 310 may be mobility.

The sensing unit 310 converts the voltage Vsen sensed according to the threshold voltage or mobility sensing drive into a digital value, and generates and outputs sensing data including the converted sensing value. Sensing data output from the sensing unit 310 may be stored in the memory 330 or provided to the compensating unit 320 .

The compensator 320 determines the characteristic value or change in the characteristic value of the driving transistor DRT in the corresponding sub-pixel SP based on the sensing data provided by the sensing unit 310 or the sensing data stored in the memory 330 and detects the characteristic value deviation. Carry out a rewarding process.

6 is a diagram for explaining dispersion compensation according to sensing characteristic values of a display device according to an exemplary embodiment of the present invention. FIG. 7 is a diagram for describing time-lapse compensation according to sensing characteristic values of a display device according to an exemplary embodiment of the present invention.

The compensator 320 generates a scatter plot of characteristic values of the driving transistor DRT in the sub-pixel SP, as shown in FIG. 6 or 7 , based on the sensing data obtained through the process as described above. can In an embodiment of the present invention, the compensator 320 may perform dispersion compensation as shown in FIG. 6 or time-lapse compensation as shown in FIG. 7 using the characteristic value scatter diagram of the driving transistor DRT.

For example, the compensator 320 may generate a scatter diagram 602 of characteristic values of the driving transistor DRT as shown in FIG. 6 based on the sensing data obtained through the process described above. The compensator 320 compares the generated scatter plot 602 with a predetermined reference scatter plot 604, and changes the deviation so that the scatter plot 602 of the characteristic value of the current driving transistor DRT is changed to be the same as the reference scatter plot 604. Compensation data capable of compensating components is generated. The compensation unit 320 may generate compensation data corresponding to a deviation change component to be changed by referring to a predetermined table or formula.

As another example, the compensator 320 may generate a scatter diagram 702 of characteristic values of the driving transistor DRT as shown in FIG. 7 based on the sensing data obtained through the process described above. The compensation unit 320 compares the generated scatter plot 702 with a predetermined reference scatter plot 704, and sets the average value m2 of the current scatter plot 602 to the average value m1 of the reference scatter plot 602. change To this end, the compensator 320 changes the level of the reference voltage Vref commonly supplied to all sub-pixels SP. The compensator 320 may determine the magnitude of the reference voltage Vref corresponding to the average value component to be changed by referring to a predetermined table or formula.

The compensation unit 320 may change image data using the determined compensation data and provide the changed data to the data driver 12 . Also, the compensator 320 may transmit the changed level of the reference voltage Vref to the voltage generator 18 so that the voltage generator 18 supplies the reference voltage Vref of the changed level.

When the sensing operation is completed in the sensing mode as described above, the compensation unit 320 provides a recovery voltage supplied to the sub-pixel SP when the sub-pixel SP operates in the sensing mode based on the reference voltage value Vref. value can be determined.

8 is a diagram illustrating a change in magnitude of a voltage applied through a data line in a sensing mode and a driving mode of a subpixel according to an embodiment of the present invention.

As shown in FIG. 8 , the recovery voltage GRAY2 is applied to each sub-pixel SP after the sensing period in the sensing mode ends. However, as described above with reference to FIG. 4 , coupling of the reference voltage Vref and the data voltage Vdata occurs in the process of applying the data voltage Vdata corresponding to the image data in the drive mode after application of the recovery voltage GRAY2. Due to this phenomenon, an over-shooting or under-shooting phenomenon of the reference voltage Vref appears. This coupling phenomenon appears in proportion to the difference value ΔV between the recovery voltage value GRAY2 and the data voltage value Vdata. To solve this problem, the compensator 320 of the display device according to the present invention adjusts the recovery voltage value GRAY2 based on the previously determined reference voltage value Vref.

In one embodiment of the present invention, the compensation unit 320 first determines whether the determined reference voltage value Vref is out of a predetermined limit range. For example, the compensator 320 may determine whether the reference voltage value Vref is between a predetermined minimum limit value and a maximum limit value.

As a result of the determination, when the reference voltage value Vref is between the minimum limit value and the maximum limit value, the compensator 320 may maintain the recovery voltage value GRAY2 at a previously set value. However, as a result of the determination, if the reference voltage value (Vref) is less than the minimum limit value or exceeds the maximum limit value, that is, if it is out of the limit range, the compensator 320 converts the recovery voltage value (GRAY2) to a new value (GRAY2'). Adjust.

In one embodiment of the present invention, the compensator 320 may set a new recovery voltage value GRAY2' by adding the adjustment value k to the previously set recovery voltage value GRAY2. At this time, the adjustment value (k) can be calculated as follows.

[Equation 1]

k = (Vref - GRAY2) × Gain

In [Equation 1], the gain value (Gain) may be set differently depending on the embodiment. The compensator 320 may determine a new recovery voltage value GRAY2' by adjusting the recovery voltage value GRAY2 based on the difference between the reference voltage value Vref and the previously set recovery voltage value GRAY2. there is.

The new recovery voltage value GRAY2' determined by the compensator 320 is transferred to the data driver 12 . Accordingly, the data driver 12 applies a new recovery voltage value GRAY2' to each pixel SP in the recovery period S2 after the sensing period ends.

Due to the application of the new recovery voltage value GRAY2', the difference value ΔV between the recovery voltage value GRAY2' and the data voltage value Vdata decreases. As the difference value ΔV between the recovery voltage value GRAY2′ and the data voltage value Vdata decreases, the aforementioned change in the reference voltage Vref that occurs when the data voltage Vdata is applied does not occur. Accordingly, generation of bright lines or dark lines is prevented.

9 is a flowchart of a control method of a display device according to an embodiment of the present invention.

Referring to FIG. 9 , the display device according to an exemplary embodiment of the present invention first drives the sub-pixel SP in a sensing mode, and senses a characteristic value of a driving transistor of the sub-pixel SP through a sensing unit 310 . (902).

Meanwhile, although not shown in the drawing, the compensator 320 applies a criterion when the sub-pixel SP operates in the driving mode based on the characteristic value of the driving transistor of the sub-pixel SP sensed by the sensing unit 310. A voltage value Vref may be determined.

Next, the compensator 320 compares the reference voltage value Vref applied when the sub-pixel SP operates in the driving mode with a predetermined limiting range (904). Subsequently, the compensator 320 determines the value of the recovery voltage supplied to the sub-pixel SP according to the comparison result in step 904 (906).

In one embodiment of the present invention, the compensator 320 calculates the adjustment value k of the recovery voltage GRAY when the magnitude of the reference voltage value Vref is out of a predetermined limit range, and the previously set recovery voltage value Adjust the size of (GRAY2) to a new recovery voltage value (GRAY2'). At this time, the compensator 320 may determine a new recovery voltage value GRAY2' by adjusting the recovery voltage value GRAY2 based on the difference between the reference voltage value Vref and the previously set recovery voltage value GRAY2. there is.

However, if the magnitude of the reference voltage value Vref is within the predetermined limit range, the compensator 320 maintains the previously set recovery voltage value GRAY2 as it is.

The compensator 320 outputs an image by supplying 908 a data voltage according to the determined recovery voltage value to the sub-pixel SP. By adjusting the recovery voltage value GRAY2 as described above, the change in the reference voltage Vref that occurs when the data voltage Vdata is applied does not occur, and the resulting bright or dark lines are prevented from occurring.

The above-described present invention, since various substitutions, modifications, and changes are possible to those skilled in the art without departing from the technical spirit of the present invention, the above-described embodiments and accompanying drawings is not limited by

Claims (10)

a display panel having a plurality of sub-pixels;
a data driver supplying data signals to a plurality of data lines disposed on the display panel;
a gate driver supplying gate signals to a plurality of gate lines disposed on the display panel;
a compensator configured to determine a recovery voltage value supplied to the subpixel when the subpixel operates in a sensing mode, based on a value of a reference voltage applied when the subpixel operates in a driving mode;
the compensation part
determining a value of the reference voltage based on a characteristic value of a driving transistor of the subpixel sensed in the sensing mode;
It is determined whether the reference voltage value is out of a predetermined limit range, and as a result of the determination, when the reference voltage value is between the minimum limit value and the maximum limit value, the recovery voltage value is maintained at the previously set value, and the determination As a result, when the reference voltage value is less than the minimum limit value or exceeds the maximum limit value, the recovery voltage value is adjusted;
supplying the adjusted recovery voltage to the data line before switching from the sensing mode to the driving mode;
display device.
According to claim 1,
the compensation part
Adjusting the recovery voltage value when the magnitude of the reference voltage value is out of a predetermined limit range
display device.
According to claim 1,
the compensation part
Adjusting the recovery voltage value based on a difference between the reference voltage value and a previously set recovery voltage value
display device.
According to claim 1,
the compensation part
Maintaining the recovery voltage value as the previously set recovery voltage value when the reference voltage value is included in the predetermined limit range
display device.
delete sensing a characteristic value of a driving transistor of the sub-pixel by driving the sub-pixel in a sensing mode;
comparing a value of a reference voltage applied when the sub-pixel operates in a driving mode with a predetermined limiting range;
determining a recovery voltage value supplied to the sub-pixel according to the comparison result; and
supplying a data voltage according to the determined recovery voltage value to the sub-pixel through a data line;
The step of determining the recovery voltage value is
determining the reference voltage value based on the characteristic value;
determining whether the reference voltage value is out of a predetermined limit range;
maintaining the recovery voltage value as a previously set value when the reference voltage value is between a minimum limit value and a maximum limit value as a result of the determination; and
Adjusting the recovery voltage value when the reference voltage value is less than the minimum limit value or exceeds the maximum limit value as a result of the determination,
Further comprising supplying the adjusted recovery voltage to the data line before switching from the sensing mode to the driving mode.
Control method of display device.
According to claim 6,
The step of determining the recovery voltage value is
Adjusting the recovery voltage value when the magnitude of the reference voltage value is out of a predetermined limit range
Control method of display device.
According to claim 6,
The step of determining the recovery voltage value is
Adjusting the recovery voltage value based on a difference between the reference voltage value and a previously set recovery voltage value.
Control method of display device.
According to claim 6,
The step of determining the recovery voltage value is
Maintaining the recovery voltage value as a previously set recovery voltage value when the reference voltage value is included in a predetermined limit range
Control method of display device.
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