KR102603408B1 - Display device and method for controlling thereof - Google Patents

Abstract

The present invention relates to a display device and a method of controlling the display device. A display device according to an embodiment of the present invention includes a display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines, the plurality of A data driving circuit for supplying image data to a data line, a gate driving circuit for supplying gate signals to the plurality of gate lines, a voltage generating circuit and the data driving circuit for generating and supplying a voltage necessary for driving the subpixel, It includes a gate driving circuit and a timing control circuit that controls the operation of the voltage generation circuit.

Description

Display device and control method of the display device {DISPLAY DEVICE AND METHOD FOR CONTROLLING THEREOF}

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

The Organic Light Emitting Diode (OLED) display device is a display device using OLED, a self-luminous element that emits light in the organic light-emitting layer by recombination of electrons and holes. It has high brightness, low driving voltage, and can be made into ultra-thin films, making it a next-generation display device. It is in the spotlight 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 between them, and a subpixel driving circuit that independently drives the OLED. The subpixel 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 size 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 organic light-emitting diodes (OLEDs) or driving transistors included in each subpixel each have unique characteristics (e.g., threshold voltage, mobility, etc.). Such circuit elements deteriorate depending on the operating time of the OLED display device, and the characteristics of each circuit element change due to deterioration. This change in the characteristics of the circuit element causes a luminance deviation between each subpixel including the circuit element, thereby lowering the overall luminance uniformity of the display panel.

In order to solve this problem, a technology is being applied that senses the characteristic values of the circuit elements included in each subpixel and compensates for the characteristic values of the circuit elements based on the sensed values. The above-described compensation process may be performed during the process of displaying an image through an OLED display device. According to the prior art, when the compensation process is applied during the image display process, a phenomenon occurs in which a specific line becomes excessively bright.

The purpose of the present invention is to provide a display device and a control method for the display device that can improve image quality by improving the phenomenon in which certain lines become excessively bright due to the application of a compensation process in the process of displaying an image through a display device. .

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

A display device according to an embodiment of the present invention includes a display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines, the plurality of A data driving circuit for supplying image data to a data line, a gate driving circuit for supplying gate signals to the plurality of gate lines, a voltage generating circuit and the data driving circuit for generating and supplying a voltage necessary for driving the subpixel, It includes a gate driving circuit and a timing control circuit that controls the operation of the voltage generation circuit.

Here, the subpixel operates in a sensing mode or a driving mode, and a recovery voltage is supplied to the subpixel in a recovery section after the sensing section ends in the sensing mode.

In one embodiment of the present invention, the timing control circuit determines the optimal reference voltage based on the magnitude of the supply reference voltage supplied to the subpixel by the voltage generation circuit and the magnitude of the feedback reference voltage measured by the voltage generation circuit. Decide on size.

Additionally, in one embodiment of the present invention, the voltage generation circuit supplies a reference voltage to the subpixel according to the size of the reference voltage set by the timing control circuit, and measures the size of the voltage actually supplied to the subpixel. It is transmitted to the timing control circuit.

Additionally, in one embodiment of the present invention, the timing control circuit determines the size of the recovery voltage based on the size of the reference voltage supplied to the subpixel.

Additionally, in one embodiment of the present invention, the timing control circuit determines the magnitude of the recovery voltage based on Equation 1 below.

[Equation 1]

GRAY2 = G×VpreR + Offset

(However, GRAY2 is the size of the recovery voltage, G is a preset gain value, VpreR is the size of the reference voltage supplied to the subpixel, and Offset is a preset offset value)

In addition, according to an embodiment of the present invention, a display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines, the plurality of data lines A method of controlling a display device including a data driving circuit for supplying image data to a display device and a gate driving circuit for supplying gate signals to the plurality of gate lines includes operating the subpixel in a sensing mode to control the driving transistor of the subpixel. Sensing a characteristic value, determining a size of a recovery voltage to be supplied in a recovery section after the sensing section ends in the sensing mode, and supplying the recovery voltage to the subpixel according to the size of the determined recovery voltage, and It includes operating the subpixel in a driving mode.

In one embodiment of the present invention, the control method of the display device is based on the size of the supply reference voltage supplied to the subpixel and the size of the feedback reference voltage measured by the voltage generation circuit. It further includes determining the magnitude of the reference voltage.

In addition, in one embodiment of the present invention, the method for controlling the display device includes supplying a reference voltage to the subpixel according to the size of a preset reference voltage and measuring the size of the voltage actually supplied to the subpixel. Includes more.

Additionally, in one embodiment of the present invention, the size of the recovery voltage is determined based on the size of the reference voltage supplied to the subpixel.

Additionally, in one embodiment of the present invention, the magnitude of the recovery voltage is determined based on the following [Equation 1].

[Equation 1]

GRAY2 = G×VpreR + Offset

(However, GRAY2 is the size of the recovery voltage, G is a preset gain value, VpreR is the size of the reference voltage supplied to the subpixel, and Offset is a preset offset value)

According to the present invention, image quality can be improved by improving the phenomenon in which a specific line becomes excessively bright due to the application of a compensation process during the process of displaying an image through a display device.

1 is a configuration diagram of a display device according to an embodiment of the present invention.
Figure 2 shows the circuit configuration of a subpixel included in a display device according to an embodiment of the present invention.
Figure 3 is a timing diagram showing the timing at which a vertical synchronization signal and a data voltage are applied to a display device in an embodiment of the present invention.
Figure 4 is a diagram showing changes in the magnitude of voltage applied through a data line in the sensing mode and driving mode of a subpixel according to the prior art.
FIG. 5 is a diagram for explaining the configuration of a display device and the operation of a subpixel according to an embodiment of the present invention.
Figure 6 shows the configuration of a source PCB and a control PCB connected to the display panel of a display device according to an embodiment of the present invention.
Figure 7 is a diagram showing changes in the magnitude of voltage applied through a data line in the sensing mode and driving mode of a subpixel in an embodiment of the present invention.
Figure 8 is a flowchart showing a control method of a display device according to an embodiment of the present invention.

The above-mentioned objects, features, and advantages will be described in detail later with reference to the attached drawings, so that those skilled in the art will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist 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 attached drawings. In the drawings, identical reference numerals are used to indicate identical or similar components.

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

Referring to the drawings, a display device 1 according to an embodiment of the present invention includes a display panel 18 that displays an image. On the display panel 18, a plurality of data lines DL and a plurality of gate lines GL are arranged to cross each other. Hereinafter, it is defined that a plurality of data lines DL are arranged in columns and a plurality of gate lines GL are arranged in rows. However, depending on the embodiment, a plurality of data lines DL are arranged in rows. It may be defined as being arranged in rows, and multiple gate lines (GL) being arranged in columns.

A plurality of data lines (DL) and a plurality of gate lines (GL) intersect each other to define a matrix-shaped subpixel area. A subpixel (SP) is disposed in each subpixel area.

Each subpixel (SP) is equipped with a thin film transistor (TFT). A data voltage is supplied from the data driving circuit 16 through the TFT provided in each subpixel SP. When the display device 1 is a liquid crystal display device, the subpixel SP may include a liquid crystal capacitor whose arrangement of liquid crystal molecules varies depending on the supplied data voltage. When the display device 1 is an organic light emitting diode display device, the subpixel SP may include an organic light emitting diode that emits light by itself by supplying a data voltage.

The data driving circuit 16 receives the data control signal (DCS) and image data (Data) from the timing control circuit 12. The data driving circuit 16 converts the image data (Data) received from the timing control circuit 12 into an analog data voltage based on the data control signal (DCS) and supplies it to the plurality of data lines (DL).

The data driving circuit 16 may include at least one source driver integrated circuit. Each source driver integrated circuit is connected to the bonding pad of the display panel 18 using the Tape Automated Bonding (TAB) method or the Chip On Glass (COG) method, or is connected to the display panel ( 18), or may be integrated and placed on the display panel 18.

Additionally, each source driver integrated circuit may be implemented using a chip on film (COF) method. In this case, one end of the film on which each source driver integrated circuit is mounted is bonded to at least one source printed circuit board (Source Printed Circuit Board), and the other end is bonded to the display panel 18.

The gate driving circuit 14 receives the gate control signal (GCS) from the timing control circuit 12. The gate driving circuit 14 generates a scan signal based on the gate control signal (GCS) and supplies the generated scan signal to each gate line (GL).

The gate driving circuit 14 may include one or more gate driver integrated circuits. Each gate driver integrated circuit is connected to the bonding pad of the display panel 18 using a tape automated bonding (TAB) method or a chip on glass (COG) method, or is implemented as a GIP (Gate In Panel) type. It can be placed directly on the display panel 18. Additionally, the gate driving circuit 14 may be integrated and disposed on the display panel 18, or may be implemented using a chip-on-film (COF) method mounted on a film connected to the display panel 18.

The timing control circuit 12 receives image data input from an external device and converts the received image data to be suitable for driving the data driving circuit 16. The converted image data (Data) is supplied to the data driving circuit 16 together with the data control signal (DCS).

Additionally, the timing control circuit 12 controls data using synchronization signals input from an external device, such as a dot clock (DCLK), a data enable signal (DE), a horizontal synchronization signal (Hsync), and a vertical synchronization signal (Vsync). A signal (DCS) and a gate control signal (GCS) are generated, and the generated data control signal (DCS) and gate control signal (GCS) are supplied to the data driving circuit 16 and the gate driving circuit 14, respectively.

The voltage generation circuit 13 generates voltages necessary for driving each subpixel SP disposed on the display panel 18, such as a driving voltage (VDD), a base voltage (VSS), and a reference voltage (VpreR), The generated voltage is supplied to each subpixel (SP). The sizes of the driving voltage (VDD), base voltage (VSS), and reference voltage (VpreR) generated by the voltage generation circuit 13 may be set differently by the timing control circuit 12.

Figure 2 shows the circuit configuration of a subpixel included in a display device according to an embodiment of the present invention.

Referring to the drawing, each subpixel (SP) includes an organic light emitting diode (OLED), a driving transistor (DRT) for driving the organic light emitting diode (OLED), a first node (N1) of the driving transistor (DRT), and a reference voltage ( The sensing transistor (SENT) is electrically connected between the reference voltage line (RVL) that supplies VpreR), the second node (N2) of the driving transistor (DRT), and the data line (DL) that supplies the data voltage (Vdata). It includes a switching transistor (SWT) electrically connected to and a storage capacitor (Cstg) electrically connected between the first node (N1) and the second node (N2) of the driving transistor (DRT).

An organic light emitting diode (OLED) includes a first electrode (eg, an anode electrode or cathode electrode), an organic layer, and a second electrode (eg, a cathode electrode or anode electrode). Additionally, organic light-emitting diodes (OLEDs) include an organic light-emitting layer that emits light on its own when a driving current flows.

The driving transistor (DRT) supplies driving current to the organic light emitting diode (OLED) to drive 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 the source node or 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 the 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 (VpreR) to the first node (N1) of the driving transistor (DRT). Additionally, the sensing transistor (SENT) may be turned on by a gate signal and 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 transmitted to the second node (N2) of the driving transistor (DRT).

At this time, the sensing transistor (SENT) and the switching transistor (SWT) may be connected to different gate lines (GL) and controlled on-off separately, or may be connected to the same gate line (GL) and 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 the data voltage (Vdata) corresponding to the image signal or a voltage corresponding thereto. .

Meanwhile, as described above, as the driving time of each subpixel (SP) increases, circuit elements such as the organic light emitting diode (OLED) and driving transistor (DRT) may deteriorate. Accordingly, the unique characteristics (e.g., threshold voltage, mobility, etc.) of circuit elements such as organic light-emitting diodes (OLEDs) and driving transistors (DRTs) may change.

Changes in the characteristics of these circuit elements cause changes in the luminance of the corresponding subpixel (SP), and differences in changes in the characteristics of the circuit elements due to differences in the degree of deterioration between the circuit elements cause luminance deviations between the subpixels (SP) and the display panel ( 110) may result in a decrease in luminance uniformity. Here, the characteristic values of the circuit element include 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 according to the present invention includes a sensing function that senses a change in characteristic value between subpixels (SP) or a difference in characteristic value between each subpixel (SP), and a function that compensates for the characteristic value of the subpixel (SP) using the sensing result. A compensation function can be provided.

When the display device 1 is driven in the sensing mode, a sensing voltage is applied to each subpixel (SP), the characteristic value of each subpixel (SP) is sensed, and compensation data is generated by reflecting the sensed characteristic value. Additionally, 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 subpixel SP, and an image is output through the display panel 10.

Figure 3 is a timing diagram showing the timing at which a vertical synchronization signal and a data voltage are applied to a display device in an embodiment of the present invention.

As described above, during image driving through the display panel 10, sensing may be performed to compensate for changes in characteristic values between subpixels (SP) or differences in characteristic values between each subpixel (SP). This sensing may be performed every blank time (Vblank) between active times (Vactive) based on the vertical synchronization signal (Vsync).

At each active time (Vactive), a data voltage (N-1 Frame Data, N Frame Data) corresponding to each frame of the image to be displayed through each subpixel (SP) is applied through the data line (DL). And at each blank time (Vblank), sensing is performed by applying sensing data. That is, during the sensing data application period (S1) in the blank time (Vblank), the sensing voltage for sensing is applied through the data line (DL). And in the sensing section (Sensing), sensing is performed using the sensing voltage applied to the sensing data application section (S1).

Figure 4 is a diagram showing changes in the magnitude of voltage applied through a data line in the sensing mode and driving mode of a subpixel according to the prior art.

Referring to the drawing, a sensing voltage for sensing is applied through the data line DL during a sensing section (Sensing) during which the subpixel (SP) operates in a sensing mode. Afterwards, when sensing is completed and the subpixel (SP) operates in driving mode, the voltage corresponding to the image data to be displayed through the subpixel (SP), that is, the data voltage (Vdata), is applied through the data line (DL). .

Additionally, when the subpixel (SP) operates in a driving mode, the reference voltage (VpreR) for driving the subpixel (SP) is supplied to the subpixel (SP) through the reference voltage line (RVL). (see Figure 2)

However, as shown in the figure, since the sensing voltage has a magnitude lower than the data voltage (Vdata), when the operation mode of the subpixel (SP) enters the driving mode, the magnitude of the voltage supplied through the data line (DL) and The difference (ΔV) in the voltage level supplied to the data line DL before the driving mode appears very large.

In this way, as the difference (ΔV) in the voltage level supplied through the data line (DL) before and after the driving mode increases, the reference voltage (VpreR) supplied through the reference voltage line (RVL) located close to the data line (DL) increases. Ripple increases. Here, as shown in the figure, ripple refers to the size of the reference voltage (VpreR) applied through the reference voltage line (RVL) simultaneously with the driving mode due to the influence of the data voltage (Vdata) that instantaneously increases through the data line (DL). This refers to the phenomenon of momentarily overshooting or undershooting and then maintaining a constant value.

As such, a phenomenon occurs in which a specific line of the display panel becomes excessively bright due to the ripple of the reference voltage (VpreR) that occurs the moment the operation mode of the subpixel (SP) changes from the sensing mode to the driving mode. Because of this, whenever the display device is driven and a sensing operation by a compensation process is performed, a specific line is displayed brightly, causing a problem in which the image quality of the display device deteriorates.

As described above, the present invention aims to improve the image quality of a display device by improving the ripple phenomenon of the reference voltage (VpreR) that occurs the moment the operation mode of the subpixel (SP) changes from the sensing mode to the driving mode.

FIG. 5 is a diagram for explaining the configuration of a display device and the operation of a subpixel according to an embodiment of the present invention.

Referring to FIG. 5, the display device according to an embodiment of the present invention includes a subpixel (SP), a sensing unit 310, a compensation unit 320, a memory 330, a reference voltage switch (SPRE), and a sampling switch ( SAMP), a timing control circuit 12, and a voltage generation circuit 13.

The sensing unit 310 senses a voltage for sensing the characteristic value or change in characteristic value of the subpixel (SP), converts the sensed voltage into a digital value, and outputs sensing data including the converted sensing value. Here, the characteristic value of the subpixel (SP) refers to 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 in some cases, may be placed outside the source driver integrated circuit.

The compensation unit 320 uses the sensing data output by the sensing unit 310 to determine the characteristic value of the subpixel (SP) or its change, and performs a compensation process to compensate for the difference in characteristic value between the subpixels (SP). The compensation unit 320 may be included inside the timing control circuit 12, and in some cases, may be placed outside the timing control circuit 12.

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

The reference voltage switch (SPRE) controls whether or not the reference voltage (VpreR) is supplied to the reference voltage line (RVL), and the sampling switch (SAMP) controls the reference voltage to sense the characteristic value of the subpixel (SP). Controls the connection between the voltage line (RVL) and the sensing unit 310.

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

Meanwhile, when the voltage of the first node (N1) of the driving transistor (DRT) is in a voltage state that reflects the characteristic value of the subpixel (SP), the reference that may be at equal potential with the first node (N1) of the driving transistor (DRT) The voltage of the voltage line RVL may also be in a voltage state that reflects the characteristic value of the subpixel SP. At this time, the line capacitor formed on the reference voltage line RVL may be charged with a voltage reflecting the characteristic value of the subpixel SP.

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). It may be the same as the applied voltage.

When the voltage of the first node (N1) of the driving transistor (DRT) becomes a voltage state that reflects 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 that reflects the characteristic value of the subpixel (SP). At this time, the reference voltage line (RVL) may be referred to as the sensing line (SL).

The sensing unit 310 senses the voltage of the first node (N1) of the driving transistor (DRT). When the sensing unit 310 is set to sense the threshold voltage for the driving transistor (DRT), the voltage sensed by the sensing unit 310 is the threshold voltage (Vth) or the threshold voltage change (ΔVth) of the driving transistor (DRT). It may be a voltage value including: Additionally, when the sensing unit 310 is set to sense 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).

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

When the display device operates in a sensing mode, the compensation process by the sensing unit 310 and the compensation unit 320 is explained as follows. First, to explain the threshold voltage sensing process of the driving transistor (DRT), when the threshold voltage sensing of the driving transistor (DRT) is driven, the first node (N1) and the second node (N2) of the driving transistor (DRT) each have a reference voltage. It is initialized with (VpreR) and the data voltage for sensing (Vdata).

Thereafter, when the reference voltage switch (SPRE) is turned off, the first node (N1) of the driving transistor (DRT) is floating. Accordingly, the voltage of the first node N1 of the driving transistor DRT increases.

The voltage of the first node N1 of the driving transistor DRT increases, then gradually decreases and becomes saturated. The saturated voltage of the first node (N1) of the driving transistor (DRT) may correspond to the difference between the data voltage (Vdata) and the threshold voltage (Vth) or the 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 the threshold voltage deviation (Δ Vth) is subtracted from the data voltage (Vdata). It may be voltage (Vdata-ΔVth).

Next, the method of sensing the mobility of the driving transistor (DRT) is explained as follows. When driving the mobility sensing of the driving transistor (DRT), the first node (N1) and the second node (N2) of the driving transistor (DRT) are initialized to the reference voltage (VpreR) and the sensing data voltage (Vdata), respectively.

Thereafter, 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 floating. Accordingly, the voltage of the first node N1 of the driving transistor DRT begins to rise.

Here, the voltage increase width (ΔV) of the first node (N1) of the driving transistor (DRT) is the voltage increase rate and varies depending on the current capability, that is, mobility, of the driving transistor (DRT). That is, the higher the current capability (mobility) of the driving transistor (DRT), the more steeply the voltage of the first node (N1) of the driving transistor (DRT) rises, so that the voltage of the first node (N1) of the driving transistor (DRT) rises more steeply for a certain period of time. ) has a large voltage increase (ΔV).

After the voltage of the first node (N1) of the driving transistor (DRT) increases for a certain period of time, the sensing unit 310 senses the increased voltage of the first node (N1) of the driving transistor (DRT). The rate of change per hour, that is, the slope, of the voltage rise width (ΔV) according to the voltage (Vsen) sensed by the sensing unit 310 may be mobility.

The sensing unit 310 converts the sensed voltage (Vsen) into a digital value according to the threshold voltage or mobility sensing drive, 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 compensation unit 320.

The compensation unit 320 generates compensation data to compensate for changes in the characteristics of the driving transistor (DRT) in the subpixel (SP) based on the sensing data provided by the sensing unit 310 or the sensing data stored in the memory 330. . The compensation unit 320 supplies a compensated data voltage Vdata obtained by applying compensation data to the data voltage based on the image data supplied from the timing control circuit 12 to the subpixel SP through the data line DL.

Meanwhile, the timing control circuit 12 can set the size of the reference voltage VperR supplied by the voltage generation circuit 13 to an optimal size. In one embodiment of the present invention, the timing control circuit 12 is configured to determine the size of the supply reference voltage, which is the size of the reference voltage supplied by the voltage generation circuit 13 to the subpixel SP, and the voltage generation circuit 13. The size of the optimal reference voltage can be determined based on the size of the measured feedback reference voltage. Below, an embodiment in which the timing control circuit 12 sets the size of the optimal reference voltage will be described with reference to FIGS. 5 and 6.

Figure 6 shows the configuration of a source PCB and a control PCB connected to the display panel of a display device according to an embodiment of the present invention.

Referring to the drawings, one or more source printed circuit boards (PCBs) 64a and 64b are connected to the display panel 18 of the display device according to an embodiment of the present invention. For convenience of explanation, only two source PCBs 64a and 64b are shown in the drawing, but the number of source PCBs connected to the display panel 18 may vary depending on the embodiment. Source driver ICs 66a and 66b are disposed on each source PCB 64a and 64b.

Additionally, the source PCBs 64a and 64b are connected to the control PCB 60 through connection members 62a to 62d, such as flexible cables. A timing control circuit 12 and a voltage generation circuit 13 are respectively disposed on the control PCB 60.

As described above, the voltage generation circuit 13 generates a reference voltage (VpreR) for driving subpixels disposed on the display panel 18. The reference voltage VpreR generated by the voltage generation circuit 13 is supplied to the source driver IC 66b through a voltage supply line 602 connected to the source driver IC 66b via a connection member 62c, The reference voltage (VpreR) passed through the source driver IC (66b) is supplied to each subpixel (SP). At this time, the timing control circuit 12 obtains the magnitude of the reference voltage supplied by the voltage generation circuit 13, that is, the magnitude of the supplied reference voltage.

Meanwhile, the voltage supply line 602 for supplying the reference voltage (VpreR) supplied by the voltage generation circuit 13 passes through the control PCB 60, the connection member 62c, and the source driver IC 66b. It is connected to the IC (66b) and has a resistance component depending on its length. Therefore, the magnitude of the voltage supplied through the voltage supply line 602 becomes smaller than the magnitude of the supply reference voltage due to the voltage drop while passing through the voltage supply line 602. Accordingly, the size of the reference voltage (VpreR) supplied by the voltage generation circuit 13, that is, the size of the supplied reference voltage, and the size of the reference voltage (VpreR) actually supplied to the source driver IC 66b and the subpixel (SP) are It changes.

The voltage generation circuit 13 measures the magnitude of the reference voltage VpreR actually supplied to the source driver IC 66b through the feedback line 604. In the present invention, the magnitude of the reference voltage (VpreR) measured by the voltage generation circuit 13 through the feedback line 604 is referred to as the feedback reference voltage. The timing control circuit 12 obtains the magnitude of the feedback reference voltage measured through the voltage generation circuit 13.

As described above, the timing control circuit 12, which obtains the magnitude of the supply reference voltage and the magnitude of the feedback reference voltage, determines the magnitude of the optimal reference voltage based on the magnitude of the supply reference voltage and the magnitude of the feedback reference voltage.

In one embodiment of the present invention, the size of the optimal reference voltage can be determined as the average of the size of the supply reference voltage and the size of the feedback reference voltage, that is, the sum of the size of the supply reference voltage and the size of the feedback reference voltage divided by 2. there is. In another embodiment, the size of the optimal reference voltage may be determined by adding a predetermined compensation voltage value to the feedback reference voltage.

The timing control circuit 12 sets the size of the determined optimal reference voltage to the size of the reference voltage VpreR supplied by the voltage generation circuit 13. Accordingly, the voltage generation circuit 13 supplies a voltage of the same size as the optimal reference voltage set by the timing control circuit 12 as the reference voltage VpreR through the voltage supply line 602. Such control allows stable voltage supply by reducing the variation in the size of the reference voltage (VpreR) due to the voltage drop by the voltage supply line 602.

Figure 7 is a diagram showing changes in the magnitude of voltage applied through a data line in the sensing mode and driving mode of a subpixel in an embodiment of the present invention.

Referring to FIG. 4, after the sensing mode in which the above-mentioned sensing operation by the sensing unit 310 is performed is terminated, the subpixel SP operates in a driving mode. However, conventionally, since the data voltage (Vdata) is applied immediately to the subpixel (SP) after the sensing mode ends, the difference in voltage magnitude (ΔV) applied to the subpixel (SP) causes the reference voltage supplied through the reference voltage line. Ripple occurs in the voltage (VpreR).

To solve this problem, in one embodiment of the present invention, as shown in FIG. 7, a recovery voltage (GRAY2) is applied to the subpixel (SP) during the recovery period (S2) after the sensing period (Sensing) ends in the sensing mode. This is supplied.

In this way, when the recovery voltage (GRAY2) is supplied to the subpixel (SP) through the recovery section (S2), the recovery voltage (GRAY2) is supplied to the subpixel (SP) through the data line (DL) when the subpixel (SP) enters the driving mode. The difference (ΔV) between the data voltage (Vdata) and the magnitude of the voltage supplied to the subpixel (SP) through the data line (DL) before the driving mode is reduced compared to the prior art.

Accordingly, as shown in FIG. 7, when the subpixel (SP) enters the driving mode, the ripple phenomenon of the reference voltage (VpreR) supplied to the subpixel (SP) is reduced or does not occur, thereby ensuring a stable supply of the reference voltage (VpreR). It becomes possible. In addition, when the ripple phenomenon of the reference voltage (VpreR) is reduced or does not occur, the phenomenon of certain lines appearing too bright when the subpixel (SP) operates in driving mode, as mentioned earlier, is improved, thereby improving the image quality of the display device. do.

Meanwhile, in one embodiment of the present invention, the timing control circuit 12 may determine the size of the recovery voltage GRAY2 based on the size of the reference voltage VpreR supplied to the subpixel SP. For example, the timing control circuit 12 may determine the size of the recovery voltage GRAY2 based on the size of the reference voltage VpreR as shown in Equation 1 below.

[Equation 1]

GRAY2 = G×VpreR + Offset

In [Equation 1], GRAY2 means the size of the recovery voltage, G means the preset gain value, and Offset means the preset offset value. The gain value (G) and offset value (Offset) may be set differently depending on the embodiment.

Also, in [Equation 1], VpreR represents the size of the reference voltage supplied to the subpixel (SP). In one embodiment of the present invention, the timing control circuit 12 may use the magnitude of the reference voltage supplied by the voltage generation circuit 13 to the source driver IC 66b, that is, the supply reference voltage, as VpreR in [Equation 1] Also, the feedback reference voltage measured by the voltage generation circuit 13 may be used as VpreR. In another embodiment, the timing control circuit 12 may use the optimal reference voltage calculated based on the supply reference voltage and the feedback reference voltage as VpreR in [Equation 1] as mentioned above.

Figure 8 is a flowchart showing a control method of a display device according to an embodiment of the present invention.

Referring to the drawings, the display device according to an embodiment of the present invention first operates the subpixel in a sensing mode to sense the characteristic value of the driving transistor of the subpixel (S802).

Next, the display device determines the size of the recovery voltage to be supplied in the recovery section after the sensing section ends in the sensing mode (S804). As described above, in the present invention, there is a recovery section after the sensing section ends in the sensing mode, and by supplying the recovery voltage to the subpixel in the recovery section, the difference in the magnitude of the voltage supplied to the data line DL before and after the driving mode is reduced compared to the prior art. reduce.

Also, in step S804, the size of the recovery voltage may be determined based on [Equation 1].

Next, the display device supplies a recovery voltage to the subpixel according to the size of the determined recovery voltage (S806). In this way, by supplying the recovery voltage through the data line (DL) before the subpixel operates in the driving mode, the ripple phenomenon that occurred in the conventional reference voltage (VpreR) is reduced, and accordingly, the phenomenon in which certain lines appear excessively bright in the conventional driving mode. This is improved.

When the recovery voltage supply is completed through the recovery period, the display device operates the subpixel in a driving mode (S808).

As described above, the present invention has been described with reference to the illustrative drawings, but the present invention is not limited to the embodiments and drawings disclosed herein, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that transformation can occur. In addition, although the operational effects according to the configuration of the present invention were not explicitly described and explained while explaining the embodiments of the present invention above, it is natural that the predictable effects due to the configuration should also be recognized.

Claims (10)

A display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines;
a data driving circuit that supplies image data to the plurality of data lines;
a gate driving circuit that supplies gate signals to the plurality of gate lines;
a voltage generation circuit that generates and supplies a voltage necessary to drive the subpixel; and
A timing control circuit that controls operations of the data driving circuit, the gate driving circuit, and the voltage generating circuit,
The subpixel operates in sensing mode or driving mode,
After the sensing period ends in the sensing mode, a recovery voltage is supplied to the subpixel in a recovery period,
The voltage generating circuit is
Supplying a reference voltage to the subpixel according to the magnitude of the reference voltage set by the timing control circuit, measuring the magnitude of the voltage actually supplied to the subpixel, and transmitting the magnitude to the timing control circuit.
display device.
According to paragraph 1,
The timing control circuit is
Determining the size of the optimal reference voltage based on the size of the supply reference voltage supplied by the voltage generation circuit to the subpixel and the size of the feedback reference voltage measured by the voltage generation circuit.
display device.
delete A display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines;
a data driving circuit that supplies image data to the plurality of data lines;
a gate driving circuit that supplies gate signals to the plurality of gate lines;
a voltage generation circuit that generates and supplies a voltage necessary to drive the subpixel; and
A timing control circuit that controls operations of the data driving circuit, the gate driving circuit, and the voltage generating circuit,
The subpixel operates in sensing mode or driving mode,
After the sensing period ends in the sensing mode, a recovery voltage is supplied to the subpixel in a recovery period,
The timing control circuit is
Determining the size of the recovery voltage based on the size of the reference voltage supplied to the subpixel
display device.
A display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines;
a data driving circuit that supplies image data to the plurality of data lines;
a gate driving circuit that supplies gate signals to the plurality of gate lines;
a voltage generation circuit that generates and supplies a voltage necessary to drive the subpixel; and
A timing control circuit that controls operations of the data driving circuit, the gate driving circuit, and the voltage generating circuit,
The subpixel operates in sensing mode or driving mode,
After the sensing period ends in the sensing mode, a recovery voltage is supplied to the subpixel in a recovery period,
The timing control circuit is
Determining the size of the recovery voltage based on [Equation 1] below:
display device.

[Equation 1]
GRAY2 = G×VpreR + Offset
(However, GRAY2 is the size of the recovery voltage, G is a preset gain value, VpreR is the size of the reference voltage supplied to the subpixel, and Offset is a preset offset value)
A display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines, a data driving circuit that supplies image data to the plurality of data lines, and In the control method of a display device including a gate driving circuit that supplies gate signals to the plurality of gate lines,
operating the subpixel in a sensing mode to sense characteristic values of a driving transistor of the subpixel;
determining the size of a recovery voltage to be supplied in a recovery section after the sensing section ends in the sensing mode;
supplying the recovery voltage to the subpixel according to the size of the determined recovery voltage; and
comprising operating the subpixel in a driving mode,
supplying a reference voltage to the subpixel according to a preset size of the reference voltage; and
Further comprising measuring the magnitude of the voltage actually supplied to the subpixel,
Control method of display device.
According to clause 6,
Further comprising determining the size of an optimal reference voltage to be supplied to the subpixel based on the size of the supply reference voltage supplied to the subpixel and the size of the feedback reference voltage measured by the voltage generation circuit.
Control method of display device.
delete A display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines, a data driving circuit that supplies image data to the plurality of data lines, and In the control method of a display device including a gate driving circuit that supplies gate signals to the plurality of gate lines,
operating the subpixel in a sensing mode to sense characteristic values of a driving transistor of the subpixel;
determining the size of a recovery voltage to be supplied in a recovery section after the sensing section ends in the sensing mode;
supplying the recovery voltage to the subpixel according to the size of the determined recovery voltage; and
comprising operating the subpixel in a driving mode,
The size of the recovery voltage is determined based on the size of the reference voltage supplied to the subpixel.
Control method of display device.
A display panel including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines, a data driving circuit that supplies image data to the plurality of data lines, and In the control method of a display device including a gate driving circuit that supplies gate signals to the plurality of gate lines,
operating the subpixel in a sensing mode to sense characteristic values of a driving transistor of the subpixel;
determining the size of a recovery voltage to be supplied in a recovery section after the sensing section ends in the sensing mode;
supplying the recovery voltage to the subpixel according to the size of the determined recovery voltage; and
comprising operating the subpixel in a driving mode,
The size of the recovery voltage is determined based on [Equation 1] below:
Control method of display device.

[Equation 1]
GRAY2 = G×VpreR + Offset
(However, GRAY2 is the size of the recovery voltage, G is a preset gain value, VpreR is the size of the reference voltage supplied to the subpixel, and Offset is a preset offset value)

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