KR102423045B1 - Organic light emitting display device, and the method for driving therof - Google Patents

Abstract

The organic light emitting display device of the present invention includes a display panel including a plurality of sub-pixels, a source driver, a timing controller, and a gamma reference voltage generator for supplying a gamma reference voltage, and changes the gamma reference voltage to obtain black in a sensing section. By changing the data voltage, there is an effect of reducing the data voltage fluctuation of the non-sensing sub-pixel and preventing the screen quality from being deteriorated.
In addition, the method for driving an organic light emitting display device according to the present invention includes the steps of checking whether a sensing section is a sensing section for sensing a characteristic value of a driving transistor disposed in each subpixel, By changing the gamma reference voltages and changing the black data voltage, the data voltage fluctuation of the non-sensing sub-pixel is alleviated, thereby preventing screen quality deterioration.

Description

Organic light emitting display device and driving method thereof

The present invention relates to an organic light emitting display device and a driving method thereof.

Recently, an organic light emitting display device, which has been in the spotlight as an organic light emitting display device, has advantages of fast response speed, high luminous efficiency, luminance, and viewing angle by using an organic light emitting diode (OLED) that emits light by itself.

In such an organic light emitting display device, subpixels including an organic light emitting diode and a driving transistor driving the same are arranged in a matrix form, and the brightness of the subpixels selected by a scan signal is controlled according to a gray level of data.

In such an organic light emitting display device, circuit elements such as an organic light emitting diode and a driving transistor in each sub-pixel each have unique characteristic values (eg, threshold voltage, mobility, etc.).

However, as the driving time of the circuit element in each sub-pixel is increased, deterioration may progress and thus a characteristic value may change, and the luminance characteristic of the corresponding sub-pixel may also be changed according to the change in the characteristic value.

Accordingly, a technology for sensing and compensating a characteristic value of a circuit element in each sub-pixel is being developed. In particular, although the characteristic value deviation of the driving transistor is compensated for by the compensation technique, the screen quality may be deteriorated due to other causes.

For example, a case in which a black data voltage applied to a non-sensing sub-pixel during a sensing period in which a characteristic value of a circuit element is sensed changes the data voltage maintained to display an image in the display period, thereby degrading the screen quality. to be.

As such, in the organic light emitting display device, there are cases in which the screen quality is deteriorated due to other causes as well as luminance deterioration due to the deterioration of the circuit elements in the sub-pixel. is required

According to the present invention, by changing the black data voltage supplied to the sensing sub-pixel and the non-sensing sub-pixel during the sensing period to be different from the driving black data voltage supplied to the display period, the fluctuation of the data voltage of the non-sensing sub-pixel is reduced to reduce screen quality. An object of the present invention is to provide an organic light emitting display device and a driving method thereof.

The organic light emitting display device of the present invention for solving the problems of the prior art as described above includes a display panel in which a plurality of data lines and a plurality of gate lines are disposed and a plurality of sub-pixels are disposed in a matrix type, and the plurality of data lines are disposed in a matrix type. a source driver for driving a line, a timing controller for controlling the source driver, and a gamma reference voltage generator for supplying a gamma reference voltage, wherein the source driver is configured to generate data supplied to the timing controller based on the gamma reference voltage. Generates corresponding gamma voltages, and each of the plurality of sub-pixels includes an organic light emitting diode and a driving transistor for driving the organic light emitting diode, and during a sensing period for sensing a characteristic value of the driving transistor, the A gamma reference voltage generator changes the gamma reference voltage, and the source driver changes and generates a gamma voltage for black data corresponding to a sub-pixel based on the changed gamma reference voltage, and applies the changed gamma voltage to the generated gamma voltage. Accordingly, a black data voltage is generated and supplied to the sub-pixels, thereby reducing the data voltage fluctuations of the non-sensing sub-pixels, thereby preventing screen quality deterioration.

In addition, in the method of driving an organic light emitting display device according to the present invention, a display panel in which a plurality of data lines and a plurality of gate lines are disposed, a plurality of subpixels are disposed in a matrix type, and a source driver for driving the plurality of data lines , in the driving method of an organic light emitting display device including a timing controller for controlling the source driver, whether the display panel is a display period for displaying an image or a sensing period for sensing characteristic values of driving transistors disposed in each sub-pixel checking, changing the gamma voltage for black data corresponding to the sub-pixel by changing the gamma reference voltages that are the basis for generating the gamma voltages when it is confirmed as the sensing period; By including the step of generating a data voltage and supplying it to the sub-pixels, there is an effect of reducing the data voltage fluctuations of the non-sensing sub-pixels and preventing screen quality deterioration.

An organic light emitting display device and a method of driving the same according to the present invention change a black data voltage supplied to a sensing subpixel and a non-sensing subpixel during a sensing period to be different from a driving black data voltage supplied to the display period, thereby providing a non-sensing subpixel It has the effect of preventing the deterioration of the screen quality by alleviating the data voltage fluctuation of the

1 is a schematic system configuration diagram of an organic light emitting display device according to the present invention.
2A and 2B are exemplary views of a subpixel structure of an organic light emitting diode display according to embodiments of the present invention.
3 is a diagram illustrating a connection structure of a sensing line and subpixels of an organic light emitting diode display according to the present invention.
FIG. 4 is a diagram for explaining a cause of a change in a data voltage of a non-sensing subpixel during a sensing period of an organic light emitting diode display.
5 is a diagram illustrating a sensing section control system of an organic light emitting display device according to the present invention.
6 is a diagram illustrating a linear gamma graph of a sensing section and a display section of an organic light emitting diode display according to the present invention.
7 is a diagram illustrating data voltages supplied to a sensing section and a display section of the organic light emitting diode display according to the present invention.
FIG. 8 is a diagram for explaining a state in which a data voltage fluctuation in a non-sensing sub-pixel of the organic light emitting diode display according to the present invention is reduced.
9 is an exemplary diagram of a display section and a sensing section of the organic light emitting diode display according to the present invention.
10 is a flowchart illustrating a method of driving an organic light emitting diode display according to the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative and the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the case in which the plural is included is included unless specifically stated otherwise.

In interpreting the components, it is interpreted as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, when the temporal relationship is described as 'after', 'following', 'after', 'before', etc., 'immediately' or 'directly' Unless ' is used, cases that are not continuous may be included.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be implemented independently of each other or may be implemented together in a related relationship. may be

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. And in the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals refer to like elements throughout.

1 is a schematic system configuration diagram of an organic light emitting diode display according to the present invention, and FIGS. 2A and 2B are exemplary views of sub-pixel structures of the organic light emitting display device according to embodiments of the present invention.

Referring to FIG. 1 , in the organic light emitting diode display 100 according to the present invention, a plurality of data lines DL and a plurality of gate lines GL are disposed, and a plurality of sub-pixels (SP) are disposed. display panel 110 , a source driver 120 driving a plurality of data lines DL, a scan driver 130 driving a plurality of gate lines GL, a source driver 120 , and a scan driver and a timing controller 140 for controlling 130 and the like.

The timing controller 140 supplies various control signals to the source driver 120 and the scan driver 130 to control the source driver 120 and the scan driver 130 .

The timing controller 140 starts a scan according to the timing implemented in each frame, and converts the input image data input from the outside according to the data signal format used by the source driver 120 to match the converted driving data DATA. ) and control the display driving data at an appropriate time according to the scan signal.

The source driver 120 drives the plurality of data lines DL by supplying the driving data voltage Vdata to the plurality of data lines DL. Here, the source driver 120 is also referred to as a 'data driver'.

The scan driver 130 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL. Here, the scan driver 130 is also referred to as a 'gate driver'.

The scan driver 130 sequentially supplies a scan signal of an on voltage or an off voltage to the plurality of gate lines GL under the control of the timing controller 140 .

When a specific gate line is opened by the scan driver 130 , the source driver 120 converts the image data received from the timing controller 140 into an analog data voltage and supplies it to the plurality of data lines DL.

Although the source driver 120 is located only on one side (eg, upper or lower side) of the display panel 110 in FIG. 1 , the source driver 120 is located on both sides (eg, upper and lower sides) of the display panel 110 according to a driving method and a panel design method. ) may be located in

Although the scan driver 130 is located only on one side (eg, left or right) of the display panel 110 in FIG. 1 , the scan driver 130 is located on both sides (eg, left and right side) of the display panel 110 according to a driving method, a panel design method, etc. may be located on the right).

The above-described timing controller 140 includes a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input data enable (DE) signal, a clock signal (CLK), etc. together with the input image data. It receives various timing signals from the outside (eg, host system).

The timing controller 140 converts the input image data input from the outside to match the data signal format used by the source driver 120 and outputs the converted image data, as well as the source driver 120 and the scan driver 130 . ), the source driver 120 and the scan driver 130 receive timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input DE signal, and a clock signal to generate various control signals. ) is output.

For example, the timing controller 140 controls the scan driver 130 , a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE). : Outputs various gate control signals (GCS: Gate Control Signal) including Gate Output Enable).

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver ICs constituting the scan driver 130 . The gate shift clock GSC is a clock signal commonly input to one or more gate driver integrated circuits and controls shift timing of a scan signal (gate pulse). The gate output enable signal GOE specifies timing information of one or more gate driver integrated circuits.

In addition, the timing controller 140 controls the source driver 120 , a source start pulse (SSP), a source sampling clock (SSC), and a source output enable signal (SOE: Source). Output Enable) and output various data control signals (DCS: Data Control Signal).

Here, the source start pulse SSP controls the data sampling start timing of one or more source driver ICs constituting the source driver 120 . The source sampling clock SSC is a clock signal that controls sampling timing of data in each of the source driver integrated circuits. The source output enable signal SOE controls the output timing of the source driver 120 .

The source driver 120 may include at least one source driver integrated circuit (SDIC) to drive a plurality of data lines.

Each source driver integrated circuit (SDIC) includes a shift register, a latch circuit, a digital-to-analog converter (DAC), an output buffer, and a gamma voltage generator (FIG. 5). see), and the like.

Each source driver integrated circuit SDIC may further include an analog-to-digital converter (ADC) in some cases.

The scan driver 130 may include at least one gate driver integrated circuit (GDIC).

Each gate driver integrated circuit GDIC may include a shift register, a level shifter, and the like.

Each subpixel SP disposed on the display panel 110 may include a circuit element such as a transistor.

For example, in the display panel 110 , each sub-pixel SP includes an organic light emitting diode (OLED) and circuit elements such as a driving transistor 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 a provided function and a design method.

2A and 2B , in the organic light emitting diode display 100 according to the present invention, each sub-pixel includes an organic light emitting diode (OLED) and a driving device for driving the organic light emitting diode (OLED). A first transistor electrically connected between a driving transistor (DRT) and a sensing line (SL) supplying a reference voltage (Vref) and a first node (N1) of the driving transistor (DRT) (T1), a second transistor T2 electrically connected between the second node N2 of the driving transistor DRT and the data line DL supplying the data voltage Vdata, and the driving transistor DRT It is configured to include a storage capacitor (Cst: Storage Capacitor) electrically connected between the first node (N1) and the second node (N2) of the.

The 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 second transistor T2 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) supplying the driving voltage EVDD, and may be a drain node or a source node.

As shown in FIG. 2A , the first transistor T1 is turned on by the first scan signal SCAN1 to apply the reference voltage Vref to the first node N1 of the driving transistor DRT. can

Also, the first transistor T1 may be used as a voltage sensing path for the first node N1 of the driving transistor DRT when it is turned on.

When the second transistor T2 is turned on by the second scan signal SCAN2 , the data voltage Vdata supplied through the data line DL is transferred to the second node N2 of the driving transistor DRT. does it

The storage capacitor Cst is electrically connected between the first node N1 and the second node N2 of the driving transistor DRT, and applies a data voltage corresponding to the image signal voltage or a voltage corresponding thereto for one frame time. can keep you

The storage capacitor Cst is not a parasitic capacitor (eg, Cgs, Cgd) which is an internal capacitor existing between the first node N1 and the second node N2 of the driving transistor DRT. It is an external capacitor intentionally designed outside the driving transistor (DRT).

On the other hand, as shown in FIG. 2B , the first transistor T1 and the second transistor T2 may be controlled together by one scan signal SCAN.

That is, the first transistor T1 and the second transistor T2 may have their gate nodes connected to the same gate line GL, and receive the same scan signal SCAN to be turned on and off together.

Meanwhile, one sensing line SL electrically connected to the drain node or the source node of the first transistor T1 may be disposed one for each sub pixel column, or for every two or more sub pixel columns. It may be arranged one by one.

For example, when one pixel is composed of 4 sub-pixels (red sub-pixel, white sub-pixel, blue sub-pixel, and green sub-pixel), the sensing line SL has 4 sub-pixel columns (red sub-pixel column, One white subpixel column, one blue subpixel column, and one green subpixel column) may be disposed.

On the other hand, in the case of the organic light emitting diode display 100 according to the present invention, as the driving time of each sub-pixel SP increases, circuit elements such as the organic light emitting diode (OLED) and the driving transistor (DRT) are deteriorated ( Degradation) may proceed.

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.

A change in the characteristic value of such a circuit element causes a change in luminance of a corresponding sub-pixel.

Here, the characteristic value (hereinafter, also referred to as “sub-pixel characteristic value”) of the circuit element may include, for example, the threshold voltage and mobility of the driving transistor DRT, and in some cases, the organic light emitting diode (OLED). may include a threshold voltage of

The organic light emitting display device 100 according to the present invention provides a sensing function for sensing (measuring) a change in a characteristic value of a sub-pixel or a characteristic value deviation between each sub-pixel, and a compensation function for compensating for a characteristic value of a sub-pixel using the sensing result. can do.

Accordingly, in the organic light emitting display device 100 of the present invention, in order to provide a function of sensing and compensating for sub-pixel characteristic values, a sub-pixel structure ( FIG. 2A or FIG. 2B ) suitable for the corresponding sub-pixel structure ( FIG. 2A or 2B ) and compensation including a sensing and compensation structure includes a circuit.

3 is a diagram illustrating a connection structure of a sensing line and sub-pixels of an organic light emitting diode display according to the present invention, and FIG. 4 explains the cause of a change in the data voltage of a non-sensing sub-pixel during a sensing period of the organic light emitting display device It is a drawing for

Referring to FIG. 3 , in the organic light emitting display device of the present invention, horizontally adjacent red (R) sub-pixels, white (W) sub-pixels, green (G) sub-pixels, and blue (B) sub-pixels are one make up pixels Each subpixel SP constituting the pixel is connected to any one of the data lines DL and to any one of the gate lines GL, and the four subpixels constituting the pixel are connected to one sensing line ( SL) in common.

Each sub-pixel SP of the organic light emitting display device may operate as a display section for displaying an image and a sensing section for sensing characteristic values of the sub-pixels.

Accordingly, as shown in FIG. 3 , in the sensing period, the scan signal SCAN (second transistor on voltage) is input through the gate line GL corresponding to each of the horizontally neighboring sub-pixels SP. Then, the sensing data voltage Vdata_SEN is supplied to the sensing subpixel through the data line DL connected to the sensing subpixel, and the sensing signal Vsen is output through the sensing line SL. The sensing sub-pixel is defined as a sub-pixel to which the sensing data voltage Vdata_SEN is supplied to sense a change in the characteristic value of the sub-pixel SP, and refers to a red (R) sub-pixel in FIG. 3 .

In addition, in order to increase sensing accuracy, a black data voltage Vdata_B is supplied to each of the non-sensing sub-pixels commonly connected to the sensing line SL. In the present invention, the driving black data voltage Vdata_BD used in the display section is higher than By generating a high black data voltage (Vdata_B) and supplying it to the non-sensing sub-pixels, degradation of the screen quality is prevented. (See the gamma curve in FIG. 6 )

Here, the non-sensing sub-pixel refers to white (W), green (G), and blue (B) sub-pixels commonly connected to the sensing line SL in FIG. 3 , but each data line DL is a column. the red (R) subpixels, white (W) subpixels, green (G) subpixels, and blue (B) subpixels because they are commonly connected to the white (W), green (G) subpixels in the direction and white (W) subpixels, green (G) subpixels, and blue (B) subpixels in the column direction for the blue subpixels are also included in the non-sensing subpixel.

In addition, the driving black data voltage Vdata_BD is a black data voltage (zero gray voltage) in the display section generated using the linear section gamma curve graph of the display section shown in FIG. 6 . In general, since the black data voltage supplied during the sensing period also uses the linear gamma curve of the display period of FIG. 6 , the driving black data voltage Vdata_BD is also supplied during the sensing period.

In this way, when sensing driving is performed on the organic light emitting display device, a result value of the sensing signal Vsen is obtained through the sensing line SL, and a process of compensating for data is performed based on the result value.

However, as shown in FIG. 6 , the driving black data voltage Vdata_BD is set to the lowest value in the gamma voltage range because it is determined from a linear gamma curve in the display section for expressing gray levels of 0 to 255.

As such, when the driving black data voltage (Vdata_BD) supplied to the non-sensing sub-pixel during the sensing period is low, the data voltage maintained in the non-sensing sub-pixel increases by a negative shift of the second transistor T2, Due to this, there is a problem of causing a defect in the speckle band in the display section.

Referring to FIG. 4 , as described above, the non-sensing sub-pixel includes sub-pixels corresponding to a gate line to which a scan signal (turn-on voltage) is not applied (off-voltage). For example, the driving black data voltage Vdata_BD is also applied to the white (W) subpixel in the column direction commonly connected to the data line DL connected to the white (W) subpixel of FIG. 3 .

As shown in FIG. 4 , although the scan signal (on voltage) is not applied to the gate line (SCAN2: OFF voltage), the threshold voltage Vth of the second transistor T2 of the non-sensing subpixel is negatively shifted ( As the negative shift is performed, the second transistor T2 is in a lightly turned-on state.

As a result, there is a problem in that the data voltage VN2 of the second node maintained for displaying an image in the display section varies through the data line DL (data shuffling failure).

In particular, as the difference (VN2-Vdata_BD) between the data voltage (VN2) and the driving black data voltage (Vdata_BD) increases, the rate of change in which the data voltage (VN2) drops in the direction of the data line (DL) increases. appears as a decrease in quality. In FIG. 4 , white (W) non-sensing sub-pixels in the column direction are shown as the center, but the same phenomenon occurs in green (G) and blue (B) non-sensing sub-pixels in the column direction.

The organic light emitting display device and the driving method thereof of the present invention provide a black data voltage higher than the driving black data voltage supplied to the non-sensing sub-pixels in a sensing period, thereby reducing the data voltage of the non-sensing sub-pixel and the black data voltage. By reducing the difference, the screen quality deterioration was prevented.

5 is a diagram illustrating a sensing section control system of an organic light emitting display device according to the present invention, and FIG. 6 is a view showing a linear gamma graph of a sensing section and a display section of the organic light emitting display device according to the present invention. 7 is a diagram illustrating data voltages supplied to a sensing section and a display section of the organic light emitting diode display according to the present invention.

Referring to FIG. 5 together with FIG. 1 , the organic light emitting display device 100 of the present invention includes a display panel 110 , a source driver 120 , a timing controller 140 , and a scan driver 130 , and a gamma reference voltage generator 503 that supplies gamma reference voltages to a source driver IC (SDIC) of the source driver 120 and a sensing section controller 500 that controls the gamma reference voltage generator 503 . . The gamma reference voltage generator 503 may be implemented as a programmable gamma IC.

In addition, a plurality of source driver ICs (SDICs) may be disposed in the source driver 120 , and a gamma voltage generator 504 configured of resistor strings for voltage division may be further included in the source driver ICs (SDIC). In the present invention, the sensing section controller 500 , the gamma reference voltage generator 503 , and the gamma voltage generator 504 may operate as one sensing section system for varying the black data voltage in the sensing section.

The sensing section control unit 500 includes a gamma reference voltage generator 503 generated by the sensing section checker 501 that checks the display section and the sensing section, and the information checked by the sensing section checker 501 . A control unit 502 that changes the reference voltages RV0, ... RV9 may be included.

The gamma voltage generator 504 generates gamma voltages V_min corresponding to 0 to 255 grays by the gamma reference voltages RV0, ... RV9 supplied from the gamma reference voltage generator 503 . ~V_max). In addition, the gamma voltages V_min to V_max are selected to correspond to grayscale values of data (image data, sensing data, or black data) supplied to the DAC disposed in the source driver IC and supplied to the timing controller 140 . . Data are converted into analog voltages (gamma voltage or grayscale voltage) by the selected gamma voltages.

More specifically, as shown in FIG. 7 , in the organic light emitting diode display of the present invention, the sensing data voltage Vdata_SEN and the black data voltage Vdata_B are applied to the sensing subpixel during the sensing period within the blank period. is supplied, and a black data voltage Vdata_B higher than the driving black data voltage Vdata_BD is supplied to the non-sensing subpixel. The blank section is partitioned based on the vertical synchronization signal Vsync, and may further include a sensing section and a section for additionally supplying recovery data for a display section.

Also, in the display period, a data voltage Vdata for displaying an image is supplied to each sub-pixel, and the data voltage Vdata includes a driving black data voltage Vdata_BD of 0 grayscale.

In the present invention, a black data voltage (Vdata_B) higher than the driving black data voltage (Vdata_BD) used in the display period is generated to prevent data voltage fluctuations occurring in the non-sensing sub-pixel during the sensing period, and thus the sensing sub-pixel and the non-sensing sub-pixel are generated. to be supplied to the pixel.

To this end, in the present invention, the gamma reference voltages that are the basis for generating the sensing data voltage Vdata_SEN and the black data voltage Vdata_BD in the sensing period are changed using the sensing period controller 500 .

5 and 6 , in the display section for displaying an image, the gamma reference voltage generator 503 generates gamma reference voltages of RV0, ... RV9, and a gamma voltage generator built in the source driver IC. By supplying to 504, a plurality of gamma voltages corresponding to 0 to 255 gray levels are generated.

Referring to the linear gamma curve of the display section of FIG. 6 , the lowest gamma voltage V_min and the highest gamma voltage V_max correspond to 0 gray and 255 gray, respectively.

In addition, the lowest gamma voltage V_min corresponds to the driving black data voltage Vdata_BD supplied to each sub-pixel in the display period, and the voltage value has a value of 0.5 [V] equal to the lowest gamma reference voltage RV0. have On the other hand, the highest gamma voltage V_max corresponding to 255 gray levels corresponds to the highest gamma reference voltage RV9 (eg, 16 [V]).

Also, in the sensing section for sensing the characteristic value of the sub-pixel, the gamma reference voltage generator 503 generates changed gamma reference voltages such as RV'0, ... RV'9 under the control of the sensing section controller 500 . and supplying it to the gamma voltage generator 504 to generate gamma voltages different from the gamma voltages generated in the display section.

As described above, since the gamma reference voltages are the basis of the gamma voltages generated by the gamma voltage generator 504, the gamma voltages are changed by changing the gamma reference voltages.

As shown in FIG. 5 , it can be seen that the lowest gamma reference voltage RV'0 in the sensing section is changed to be higher than the lowest gamma reference voltage RV0 in the display section. When the lowest gamma reference voltage RV'0 is changed in the sensing section, the next higher gamma reference voltages are also sequentially changed (RV'1, ... RV'9). This is because the lowest gamma reference voltage is changed from RV0 to RV'0 in the sensing section, and when the voltage of RV'0 becomes equal to or greater than the gamma reference voltage of RV1, a linear gamma curve is not generated. Accordingly, when the lowest gamma reference voltage is changed (RV0->RV'0), the subsequent gamma reference voltages RV'1, ... RV'9 must also be sequentially changed.

6 shows a linear gamma curve for use during a sensing period according to the present invention. In the present invention, it can be seen that the lowest gamma voltage V_min' corresponding to the black data voltage Vdata_B in the sensing section is higher than the lowest gamma voltage V_min corresponding to the driving black data voltage Vdata_BD in the display section.

According to the present invention, the black data voltage Vdata_B may be determined in a range higher than the driving black data voltage Vdata_BD, without affecting the sensing accuracy. For example, the black data voltage Vdata_B in the sensing period may be determined in the range of 1 to 5 [V]. In addition, the highest gamma reference voltage (V_max: highest gamma reference voltage (RV'9) in the sensing section) corresponding to 255 grays in the sensing section is the highest gamma reference voltage (RV9: yes, 16[ V]).

As described above, in the present invention, the gamma voltages generated by the gamma voltage generator 504 are changed by changing the gamma reference voltages of the gamma reference voltage generator 503 during the sensing period. In addition, the black data voltage Vdata_B supplied to the non-sensing sub-pixel is changed to be higher than the driving black data voltage Vdata_BD in the display period by using the changed gamma voltages. As a result, the difference between the data voltage and the black data voltage Vdata_B in the non-sensing subpixel during the sensing period is reduced, thereby reducing the rate of change of the data voltage.

Accordingly, in the present invention, the data voltage fluctuation of the non-sensing sub-pixels is reduced in the sensing period, thereby preventing screen quality deterioration in the display period displaying an image.

FIG. 8 is a diagram for explaining a state in which a data voltage variation in a non-sensing sub-pixel of the organic light emitting diode display according to the present invention is reduced.

Referring to FIG. 8 together with FIG. 7 , in the organic light emitting diode display of the present invention, the sensing data voltage and the black data voltage Vdata_B higher than the driving black data voltage Vdata_BD are supplied to the sensing sub-pixels during the sensing period.

Also, a black data voltage Vdata_B higher than the driving black data voltage Vdata_BD is supplied to the non-sensing subpixels during the sensing period.

Accordingly, the black data voltage Vdata_B supplied to the non-sensing sub-pixel during the sensing period is also supplied to the non-sensing sub-pixel to which the scan signal is not supplied (SCAN2: OFF voltage) as shown in FIG. 8 .

As described above, the black data voltage Vdata_B higher than the driving black data voltage Vdata_BD supplied to the non-sensing subpixel is supplied, so that the difference between the data voltage VN2 of the second node and the black data voltage Vdata_B is the driving black The data voltage Vdata_BD is reduced compared to when it is supplied.

For example, if the driving black data voltage Vdata_B in FIG. 4 is 0.5 [V] and the black data voltage Vdata_B in FIG. 8 is 3 [V], the data voltage VN2 of the non-sensing sub-pixel and The difference between the black data voltage Vdata_B is reduced by 2.5 [V], so that the rate of change of the data voltage Vdata of the non-sensing sub-pixel is reduced.

Accordingly, the organic light emitting display device and the driving method thereof of the present invention reduce the rate of change of the data voltage VN2 maintained in the non-sensing sub-pixel to which the scan signal is not supplied, thereby preventing screen quality deterioration in the display section. there is

9 is an exemplary diagram of a display section and a sensing section of the organic light emitting diode display according to the present invention.

As shown in FIG. 9 , the sensing period in which the black data voltage Vdata_B higher than the driving black data Vdata_BD described in the present invention is supplied to the non-sensing sub-pixels is real-time sensing within the blank period that exists during image driving. It may be a period (RTS: Real Time Sensing Period).

More specifically, the sensing section may exist in a blank section between display sections in which an image is displayed based on the vertical synchronization signal Vsync.

However, this is not fixed and may be performed in each of the off-sensing period OFFS for sensing the threshold voltage or the on-sensing period ONS for sensing mobility and the real-time sensing period RTS.

As described above, in the present invention, separate linear gamma curves are generated corresponding to the display section for displaying an image and the sensing section for sensing the characteristic values of the subpixels, and the black data voltage supplied to the non-sensing subpixels during the sensing section is driven black By setting the data voltage higher than the data voltage, there is an effect of minimizing the fluctuation of the data voltage generated in the non-sensing sub-pixel.

10 is a flowchart illustrating a method of driving an organic light emitting display device according to the present invention.

Referring to FIG. 10 , the method of driving an organic light emitting display device according to the present invention includes the steps of determining whether a sensing section or a display section is a sensing section or a display section by a sensing section checker disposed in the sensing section control section (S1001, S1002), and the sensing section , a linear section gamma curve corresponding to the sensing section is generated by changing the gamma reference voltages of the gamma reference voltage generator disposed in the organic light emitting display device and changing the gamma voltages generated by the gamma voltage generator (S1003). ).

A black data voltage (Vdata_B) higher than the driving black data voltage (Vdata_BD) used in the display section is generated according to the sensing section gamma curve (S1004), and the black data voltage (Vdata_B) is supplied to the sensing subpixel and the non-sensing subpixel during the sensing section for sensing. Driving is performed (S1005).

On the other hand, if it is confirmed as a display section by the sensing section check unit, a data voltage and a driving black data voltage (Vdata_BD) are generated according to the display section linear gamma curve generated by preset gamma reference voltages, and an image is displayed ( S1006).

Also, although the present invention has focused on changing the gamma reference voltages to increase the gamma voltage (gray voltage) corresponding to the black data, the black data voltage is changed according to the linear gamma curve of the display section by changing the black data value. may generate a voltage different from the driving black data voltage.

As described above, in the organic light emitting display device and the driving method thereof according to the present invention, by changing the black data voltage supplied to the sensing sub-pixel and the non-sensing sub-pixel during the sensing period to be different from the driving black data voltage supplied to the display period, the ratio It has the effect of preventing the deterioration of the screen quality by mitigating the data voltage fluctuations of the sensing sub-pixels.

The above description and the accompanying drawings are merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains may combine the configuration within a range that does not depart from the essential characteristics of the present invention. , various modifications and variations such as separation, substitution and alteration will be possible. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: organic light emitting display device
110: display panel
120: source driver
130: scan driver
140: timing controller
500: sensing section control unit
503: Gamma reference voltage generator

Claims (8)

a display panel in which a plurality of data lines and a plurality of gate lines are disposed, and a plurality of subpixels are disposed in a matrix type;
a source driver driving the plurality of data lines;
a timing controller controlling the source driver; and
a gamma reference voltage generator for supplying a gamma reference voltage;
The source driver is
generating gamma voltages corresponding to data supplied to the timing controller based on the gamma reference voltage;
Each of the plurality of sub-pixels,
It is configured to include an organic light emitting diode and a driving transistor for driving the organic light emitting diode,
The gamma reference voltage generator generates a first gamma reference voltage in a display period in which the display panel displays an image, and a second gamma reference voltage having a higher level than the first gamma reference voltage in a sensing period in which a characteristic value of the driving transistor is sensed. generate a reference voltage,
The source driver supplies the driving black data voltage generated based on the first gamma reference voltage to the sub-pixels in the display section, and applies the black data voltage generated based on the second gamma reference voltage to the sub-pixels in the sensing section. An organic light emitting display device that supplies pixels. According to claim 1,
The sub-pixel to which the black data voltage is supplied includes a sensing sub-pixel and a non-sensing sub-pixel,
The sensing subpixel is
receiving a sensing data voltage for sensing the characteristic value of the driving transistor during the sensing period, and then receiving the black data voltage;
The non-sensing sub-pixel is
An organic light emitting display device receiving the black data voltage during the sensing period. According to claim 1,
and a sensing period controller configured to check the sensing period to generate the first gamma reference voltage in the display period by the gamma reference voltage generator and to generate the second gamma reference voltage in the sensing period. display device. delete a display panel in which a plurality of data lines and a plurality of gate lines are disposed, and a plurality of subpixels are disposed in a matrix type;
a source driver driving the plurality of data lines; and
In the driving method of an organic light emitting display device including a timing controller for controlling the source driver,
determining whether the display panel is a display period for displaying an image or a sensing period for sensing characteristic values of driving transistors disposed in each sub-pixel;
generating a second gamma reference voltage having a higher level than the first gamma reference voltage generated in the display period when it is confirmed as the sensing period, and changing the gamma voltage for black data corresponding to the sub-pixel;
and generating a black data voltage of a higher level than the driving black data voltage supplied to the display period according to the changed gamma voltage and supplying the black data voltage to the sub-pixels in the sensing period. 6. The method of claim 5,
The sub-pixel to which the black data voltage is supplied includes a sensing sub-pixel and a non-sensing sub-pixel,
supplying the sensing data voltage and the black data voltage for sensing the characteristic value of the sensing subpixel to the sensing subpixel during the sensing period;
A method of driving an organic light emitting display device for supplying the black data voltage to the non-sensing sub-pixels during the sensing period. delete According to claim 1,
The first gamma reference voltage and the second gamma reference voltage are
An organic light emitting display device corresponding to the lowest gamma voltage among gamma voltages corresponding to a plurality of grayscales.

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