KR102604733B1 - Organic Light Emitting Display And Driving Method Of The Same - Google Patents

Abstract

The present invention includes a register storing color coordinates of pure color data; And when implementing a target color in which at least two or more pure colors are mixed, a driving pure color or a non-driving pure color is distinguished by referring to the color coordinates of the pure color data, and the driving pure color is predominantly reproduced among the driving pure colors and the non-driving pure colors. and a timing controller that increases the black data of the second sub-pixel, in which the non-driving pure color is predominantly reproduced, compared to the black data of one sub-pixel, wherein the black data turns off the driving element included in each sub-pixel. Indicates available data.

Description

Organic light emitting display device and driving method {Organic Light Emitting Display And Driving Method Of The Same}

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

The active matrix type organic light emitting display device includes an organic light emitting diode (hereinafter referred to as “OLED”) and has the advantages of fast response speed, high luminous efficiency, brightness, and viewing angle.

OLED, a light-emitting device, includes an anode electrode and a cathode electrode, and an organic compound layer (HIL, HTL, EML, ETL, EIL) formed between them. The organic compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer. EIL). When a driving voltage is applied to the anode and cathode electrodes, holes passing through the hole transport layer (HTL) and electrons passing through the electron transport layer (ETL) are moved to the emitting layer (EML) to form excitons, and as a result, the emitting layer (EML) Visible light is generated.

An organic light emitting display device arranges subpixels, each containing an OLED, in a matrix form and adjusts the luminance of the subpixels according to the gradation of image data. Each subpixel includes a driving TFT (Thin Film Transistor) as a driving element for controlling the current flowing through the OLED. The threshold voltage (hereinafter referred to as Vth) characteristics of the driving TFT deteriorates as driving time elapses and is shifted in the direction of increasing from the initial value (hereinafter referred to as the (+) direction) or in the direction decreasing from the initial value (hereinafter referred to as the positive direction). , (-) direction). If the Vth characteristics of the driving TFT are shifted, the current generated by the driving TFT is distorted, making it impossible to realize the desired image.

Such conventional organic light emitting display devices have the following problems.

First, conventional organic light emitting display devices have a problem of increasing or decreasing brightness due to insufficient compensation margin for Vth shift of the driving element.

Specifically, one pixel is formed by four subpixels (hereinafter referred to as four-color subpixels) that respectively reproduce R (red), G (green), B (blue), and W (white). In this case, as shown in FIG. 1, when the panel is driven, up to three of the four subpixels are driven to reproduce the desired target color. When a desired color is realized by driving up to three subpixels among the four primary color subpixels, there is always a non-driving subpixel. In the driving subpixel, the voltage between the gate and source of the driving element (hereinafter referred to as Vgs) is greater than the threshold voltage, so the driving element is turned on, a current flows through the driving element, and the OLED emits light due to this current. On the other hand, in a non-driving subpixel, since the Vgs of the driving element is less than the threshold voltage (hereinafter referred to as Vth), the driving element is turned off and no current flows through the driving element. Since the OLED of the non-driving subpixel does not receive current, it does not emit light and reproduces black color.

In the case of a non-driving subpixel, the Vth (-)shift level increases due to light coming from neighboring driving subpixels, resulting in insufficient compensation margin and an abnormal increase in luminance. of non-driving subpixels. The Vth (-) shift level is inversely proportional to the value of Vgs (hereinafter referred to as black Vgs) applied when implementing black color, that is, black data. of non-driving subpixels. In order to minimize the Vth (-)shift level, black black data must be increased to the maximum within a range smaller than Vth. Additionally, in order to increase black data, the option value added to the video data must be increased. However, additional option values for adjusting the current black data are commonly applied to the four primary color subpixels. Accordingly, when increasing the black data, the Vth (-) shift level of the non-driving subpixel may decrease, but the Vth (+) shift level of the driving subpixel increases. If the Vth (+) shift level of the driving subpixel increases, the luminance may deteriorate abnormally due to insufficient compensation margin.

Second, if the Vth of the driving element is continuously shifted as the driving time elapses, even if the Vth compensation margin is sufficient, the output voltage margin of the data driving circuit decreases and irregular spots due to the increase in luminance, as shown in Figure 2, occur in the shifted area. Here, the Vth compensation margin is a value included within the output voltage margin of the data driving circuit.

Therefore, the purpose of the present invention is to change the Vth shift level of the driving element by differentiating the black data of the relatively more driven subpixels from the relatively less driven subpixels when implementing a target color that is a mixture of at least two or more pure colors. The goal is to provide an organic light emitting display device and a driving method thereof that can minimize and suppress abnormal luminance increase or decrease in luminance.

Another object of the present invention is to secure the output voltage margin of the data driving circuit by varying the black data in accordance with the Vth shift level of the driving element according to changes over time, thereby solving the reliability problem due to insufficient output voltage margin of the data driving circuit. The object is to provide an organic light emitting display device and a method of driving the same.

In order to achieve the above object, an organic light emitting display device according to an embodiment of the present invention includes a register that stores color coordinates of pure color data; And when implementing a target color in which at least two or more pure colors are mixed, a driving pure color or a non-driving pure color is distinguished by referring to the color coordinates of the pure color data, and the driving pure color is predominantly reproduced among the driving pure colors and the non-driving pure colors. and a timing controller that increases the black data of the second sub-pixel, in which the non-driving pure color is predominantly reproduced, compared to the black data of one sub-pixel, wherein the black data turns off the driving element included in each sub-pixel. Indicates available data.

The timing controller is configured to set the black data voltage to be applied to the gate electrode of the driving element of the first subpixel to the source electrode of the driving element of the first subpixel when the non-driving pure color is reproduced in the first subpixel. The black data of the first subpixel is set to be lower than the reference voltage to be applied to.

The timing controller is configured to set the black data voltage to be applied to the gate electrode of the driving element of the second subpixel to the source electrode of the driving element of the second subpixel when the non-driving pure color is reproduced in the second subpixel. Black data of the second subpixel is set to be equal to the reference voltage to be applied to .

The organic light emitting display device according to another embodiment of the present invention is based on the current black data of the driving element, the first threshold for the threshold voltage (+) shift amount of the driving element, and the threshold voltage (-) shift amount of the driving element. a register storing a second threshold value and a variable section for black data of the driving element; A sensing unit that senses the current of the driving element according to a preset gate-source voltage; and deriving the threshold voltage shift amount of the driving element based on the current sensing result of the driving element, and if the threshold voltage shift amount is greater than the first threshold, black data of the driving element is stored in the current within the variable section. a timing controller that lowers the black data of the driving element to a level lower than the black data and, when the threshold voltage shift amount is smaller than the second threshold, raises the black data of the driving element to the current black data within the variable period, wherein the black data causes the driving element to Indicates data that can be turned off.

The timing controller lowers the black data of the driving device to be lower than the current black data within the variable section so that the black data voltage to be applied to the gate electrode of the driving device is lower than the black data voltage according to the current black data.

The timing controller raises the black data of the driving device higher than the current black data within the variable section so that the black data voltage to be applied to the gate electrode of the driving device is higher than the black data voltage according to the current black data.

A method of driving an organic light emitting display device according to an embodiment of the present invention includes storing color coordinates of pure color data; And when implementing a target color in which at least two or more pure colors are mixed, a driving pure color or a non-driving pure color is distinguished by referring to the color coordinates of the pure color data, and the driving pure color is predominantly reproduced among the driving pure colors and the non-driving pure colors. A step of increasing the black data of a second sub-pixel in which the non-driving pure color is predominantly reproduced compared to the black data of one sub-pixel, wherein the black data can turn off the driving element included in each sub-pixel. Indicates the data available.

A method of driving an organic light emitting display device according to another embodiment of the present invention includes current black data of the driving element, a first threshold value for a (+) shift amount of the threshold voltage of the driving element, and a threshold voltage (-) of the driving element. storing a second threshold for a shift amount and a variable section for black data of the driving element; Sensing the current of the driving element according to a preset gate-source voltage; and deriving the threshold voltage shift amount of the driving element based on the current sensing result of the driving element, and if the threshold voltage shift amount is greater than the first threshold, black data of the driving element is stored in the current within the variable section. lowering the black data than the black data and, when the threshold voltage shift amount is less than the second threshold, raising the black data of the driving element to the current black data within the variable section, wherein the black data turns the driving element. Indicates data that can be turned off.

In the present invention, when implementing a target color that is a mixture of at least two or more pure colors, the black data of the relatively more driven subpixel and the relatively less driven subpixel are differentiated from each other to minimize the Vth shift level of the driving element and prevent abnormal The increase or decrease in luminance can be suppressed.

Furthermore, the present invention secures the output voltage margin of the data driving circuit by varying the black data according to the Vth shift level of the driving element according to changes over time, thereby solving the reliability problem due to insufficient output voltage margin of the data driving circuit.

Figure 1 is a diagram showing an example in which a target color is implemented by mixing two or more pure colors on color coordinates.
FIG. 2 is a diagram showing that reliability issues such as display blurring occur when the Vth change exceeds the output voltage margin of the data driving circuit.
Figure 3 is a diagram showing a partial configuration of an organic light emitting display device according to an embodiment of the present invention.
Figure 4 is a diagram showing a method of driving an organic light emitting display device according to an embodiment of the present invention.
Figure 5 is a diagram showing an example in which the driving subpixel varies depending on the area of the white target color on the color coordinates.
Figure 6 is a diagram showing a partial configuration of an organic light emitting display device according to another embodiment of the present invention.
Figure 7 is a diagram showing a method of driving an organic light emitting display device according to another embodiment of the present invention.
Figure 8 is a diagram showing an example of the output voltage range set in the data driving circuit of the present invention.
Figure 9 is a simulation result diagram showing that the threshold voltage shift level of the driving element according to change over time varies depending on the setting value of black Vgs.
10 and 11 are diagrams for explaining the overall configuration of an organic light emitting display device according to the present invention.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, of course, the present invention is not limited to the embodiments disclosed below and can be implemented in various different forms. These embodiments are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the present invention of the scope of the invention, so that the present invention will be defined by the scope of the claims. It's just that.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in the specification are used, other parts may be added unless '~ only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship between two parts is described as 'on top', 'on top', 'at the bottom', 'next to ~', 'right next to' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used.

Although first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are merely used to distinguish one component from another.

Each of the features of the various embodiments of the present invention can be combined or combined with each other partially or entirely, and various technical interconnections and operations are possible, and each embodiment may be implemented independently of each other or together in a related relationship. It may be possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

Figure 3 is a diagram showing a partial configuration of an organic light emitting display device according to an embodiment of the present invention. Figure 4 is a diagram showing a method of driving an organic light emitting display device according to an embodiment of the present invention. And, Figure 5 is a diagram showing an example in which the driving subpixel varies depending on the area of the white target color on the color coordinates.

3 to 5, an organic light emitting display device according to an embodiment of the present invention includes a resistor 11 and a timing controller 12.

The register 11 stores the color coordinates of pure color data (S1). The present invention measures the color coordinates of pure colors when generating an optical compensation file. Pure colors may include red (R), green (G), blue (B), and white (W), as shown in FIG. 5 . The present invention generates an optical compensation file and stores it in the register 11. The optical compensation file includes settings for subpixels that operate for the color to be expressed.

When implementing a target color in which at least two or more pure colors are mixed, the timing controller 12 distinguishes between a driving pure color or a non-driving pure color (i.e., a pure color displayed as black) by referring to the color coordinates of the pure color data (S12). For example, when the target color is white, the timing controller 12 sets driving and non-driving subpixels for each white target area by referring to the color coordinates of the pure color data stored in the register 11. A driving subpixel refers to a subpixel used when driving a white target value. In FIG. 5, areas ①, ②, and ③ are areas for the white target, and marked with boxes are subpixels expressing colors corresponding to each area. If the white target is in area ①, the driving subpixels are W, G, and B subpixels, and the non-driving subpixels are R. If the white target is in area ②, the driving subpixels are W, R, and B subpixels, and the non-driving subpixels are G. If the white target is in area ③, the driving subpixels are W, R, and G subpixels, and the non-driving subpixels are B. The R subpixel in area ①, the G subpixel in area ②, and the B subpixel in area ③ are subpixels that display non-driving pure colors and reproduce black.

The timing controller 12 determines driving and non-driving sub-pixels according to the white target area, and compares the black data of the first sub-pixel in which the driving pure color is predominantly reproduced to the non-driving pure color (the second sub-pixel in which the driving pure color is predominantly reproduced). The black data of the pixel is increased (S13), where the black data indicates data that can turn off the driving element included in each subpixel.

In the first subpixel where the driving pure color is predominantly reproduced, the Vth of the driving element is (+) shifted. This first subpixel does not always reproduce only driving pure colors, and may reproduce non-driving pure colors depending on the image. However, in the case of the first subpixel, the time for displaying the driving pure color is relatively longer than the time for displaying the non-driving pure color.

On the other hand, in the second subpixel where non-driving pure colors are predominantly reproduced, the Vth of the driving element is (-) shifted. This second subpixel does not always reproduce only non-driving pure colors, and may reproduce driving pure colors depending on the image. However, in the case of the second subpixel, the time to display the non-driving pure color is relatively longer than the time to display the driving pure color.

To minimize the Vth (+)shift level in the first subpixel and the Vth (-)shift level in the second subpixel, the timing controller 12 controls the blackness of the first subpixel when it reproduces the non-driving pure color. The data is relatively lowered, and the black data when the second subpixel reproduces non-driving pure colors is relatively increased. In other words, the timing controller 12 increases the black data of the second sub-pixel higher than the black data of the first sub-pixel.

When the non-driving pure color is reproduced in the first subpixel, the timing controller 12 determines that the black data voltage to be applied to the gate electrode of the driving element of the first subpixel is applied to the source electrode of the driving element of the first subpixel. The black data of the first subpixel can be set to be lower than the reference voltage. For example, when the reference voltage is 2V, the timing controller 12 may set the black data of the first subpixel so that the black data voltage to be applied to the gate electrode of the driving element of the first subpixel is lower than 2V.

When the non-driving pure color is reproduced in the second sub-pixel, the timing controller 12 determines that the black data voltage to be applied to the gate electrode of the driving element of the second sub-pixel is applied to the source electrode of the driving element of the second sub-pixel. The black data of the second subpixel can be set to be equal to the reference voltage. For example, when the reference voltage is 2V, the timing controller 12 may set the black data of the second subpixel so that the black data voltage to be applied to the gate electrode of the driving element of the second subpixel is 2V.

In this way, the timing controller 12 may set different option values for each subpixel in order to differentiate black data between subpixels that are driven relatively more and subpixels that are driven relatively less. Through this, by minimizing the black data of the (+)shifting subpixel and maximizing the black data of the (-)shifting subpixel, it is possible to lower the Vth shift level of the driving device and suppress abnormal luminance increase or decrease in luminance. Figure 6 is a diagram showing a partial configuration of an organic light emitting display device according to another embodiment of the present invention. Figure 7 is a diagram showing a method of driving an organic light emitting display device according to another embodiment of the present invention. Figure 8 is a diagram showing an example of the output voltage range set in the data driving circuit of the present invention.

Referring to FIGS. 6 to 8 , an organic light emitting display device according to another embodiment of the present invention includes a resistor 21, a timing controller 22, a sensing unit 23, and a display panel 24.

The register 21 includes current black data of the driving element, a first threshold value for the positive (+) shift amount of the threshold voltage of the driving element, a second threshold value for the (-) shift amount of the threshold voltage of the driving element, and the The variable section for the black data of the driving element is stored (S21, S22, S23).

Black data indicates data that can turn off the driving element included in each subpixel.

The first threshold and the second threshold are voltage values belonging to the compensation voltage margin. The compensation voltage margin may be set to a voltage range within the output voltage range of the data driving circuit. For example, as shown in FIG. 8, the compensation voltage margin may be set to one voltage range (RG2) belonging to the output voltage range (FRB) of the data driving circuit. The remaining voltage range (RG1) excluding the compensation voltage margin (RG2) from the output voltage range (FRB) of the data driving circuit is used as a voltage range for generating gray scale expression voltages. The compensation voltage margin (RG2) is a NBTiS (Negative Bias Temperature illumination Stress) compensation margin (RA) to compensate for a shift in the direction in which the Vth of the driving element decreases from the initial value (hereinafter, the (-) direction), and the driving element PBTS (Positive Bias Temperature Stress) compensation margin (RC) to compensate for the shift of the threshold voltage of the TFT in the increasing direction (hereinafter, (+) direction) from the initial value, the NBTiS compensation margin (RA), and the PBTS The initial spread between the compensation margin (RC) includes the compensation margin (RB). Here, the NBTiS compensation margin and the PBTS compensation margin (RC) are voltage margins for compensating for changes in the threshold voltage (Vth) of the driving TFT (DT) over driving time. And, the initial dispersion compensation margin (RB) is a voltage margin for compensating for the threshold voltage (Vth) deviation of the driving TFTs (DTs) according to process characteristics.

As an example, as shown in FIG. 8, the first threshold value (TH1) may be set to 2.72V, which is 80% of the PBTS set value (3.4V), and the second threshold value (TH2) may be set to (-) NBTis set value (-) It can be set to -0.8V, which is 80% of -1.0V).

The variable section for black data corresponds to the variable section of the black data voltage to be applied to the gate electrode of the driving element. And, the variable section of the black data voltage belongs to the gray scale voltage range (RG1) of the data driving circuit.

The timing controller 22 drives the display panel 24 by applying Vgs, which can turn on the driving element, to the display panel 24 while applying the currently set black data (S24).

The sensing unit 23 senses the current flowing through the driving element according to the preset Vgs so that the driving element can be turned on (S25). The sensing unit 23 may include a known voltage sensing type or a current sensing type. The voltage sensing type can sense the voltage charged at a specific node of a subpixel as an analog sensing voltage according to set sensing conditions. The current sensing type can obtain an analog sensing voltage by directly sensing the current flowing in a specific node of a subpixel according to set sensing conditions. The sensing unit 23 may simultaneously process a plurality of analog sensing values in parallel using a plurality of ADCs, or sequentially process a plurality of analog sensing values in series using one ADC. There is a trade-off relationship between the sampling rate of the ADC and the accuracy of sensing. A parallel processing ADC can slow down the sampling rate compared to a serial processing ADC, which is advantageous in improving sensing accuracy. The ADC can be implemented as a flash type ADC, an ADC using a tracking technique, or a successive approximation register type ADC. The ADC converts the analog sensing voltage into digital sensing data and supplies it to the timing controller 22.

The timing controller 22 derives the threshold voltage shift amount (ΔVth) of the driving element based on the current sensing result of the driving element, and when the threshold voltage shift amount (ΔVth) is greater than the first threshold value (TH1) The black data of the driving element is lowered than the current black data within the variable section, and when the threshold voltage shift amount (ΔVth) is less than the second threshold value (TH2), the black data of the driving element is lowered within the variable section. Increasing the current black data above (S26, S27).

The timing controller 22 lowers the black data of the driving element lower than the current black data within the variable section, thereby lowering the black data voltage to be applied to the gate electrode of the driving element than the black data voltage according to the current black data. You can.

The timing controller 22 increases the black data voltage of the driving element higher than the current black data within the variable section, thereby increasing the black data voltage to be applied to the gate electrode of the driving element higher than the black data voltage according to the current black data. You can.

With the changed black data applied, the timing controller 22 applies Vgs, which can turn on the driving element, to the display panel 24 to drive the display panel 24 (S28).

Figure 9 is a simulation result diagram showing that the threshold voltage shift level of the driving element according to change over time varies depending on the setting value of black Vgs.

Referring to the simulation results in FIG. 9, when black Vgs is set to -0.1V, the Vth of the driving element shifts (+), and when black Vgs is set to -0.6V, the Vth of the driving element shifts (-). can be seen. This means that as the black data is set relatively high, the Vth of the driving device shifts (+), and as the black data is set relatively low, the Vth of the driving device shifts (-).

Therefore, if the black Vgs is appropriately varied between -0.6V and -0.1V according to the threshold voltage shift amount (ΔVth), the Vth of the driving element will approach the initial value before deterioration, and the Vth shift level of the driving element can be minimized. there is.

10 and 11 are diagrams for explaining the overall configuration of an organic light emitting display device according to the present invention.

Referring to FIGS. 10 and 11 , the organic light emitting display device according to the present invention may include a display panel 100, a timing controller 110, a data driving circuit 120, and a gate driving circuit 130. The timing controller 110 includes the registers and timing controller of FIGS. 3 and 6. The data driving circuit 120 includes the sensing unit of FIGS. 3 and 6. The display panel 100 includes the display panel of FIG. 6 .

In the display panel 100, a plurality of data lines 140 and sensing lines 200 and a plurality of gate lines 150 intersect, and subpixels P are arranged in a matrix form in each intersection area. to form a pixel array.

The subpixels (P) may include an R subpixel (P) for red display, a W subpixel (P) for white display, a G subpixel (P) for green display, and a B subpixel (P) for blue display. there is. The R subpixel (P), W subpixel (P), G subpixel (P), and B subpixel (P) may constitute one pixel. Each subpixel P may be connected to one of the data lines 140, one of the sensing lines 200, and one of the gate lines 150. Each subpixel (P) may be electrically connected to the data line 140 and the sensing line 200 according to the gate signal (SCAN) supplied from the gate line 150.

The sensing line 200 may be shared by multiple subpixels P according to the sensing line sharing structure as shown in FIG. 11 . For example, one sensing line 200 forms a pixel and is shared by the horizontally neighboring R subpixel (P), W subpixel (P), G subpixel (P), and B subpixel (P). You can. According to the sensing line sharing structure, pixels arranged on the same horizontal line are connected to different sensing lines, and subpixels (P) constituting the same pixel may share the same sensing line. In this way, the sensing line sharing structure in which one sensing line 200 is assigned to each subpixel is easier to secure the aperture ratio of the display panel than the sensing line independent structure. Various other variations of the sensing line sharing structure are possible.

Meanwhile, although not shown in the drawing, the sensing line 200 may be individually connected to a plurality of subpixels P according to an independent sensing line structure. According to the sensing line independent structure, multiple subpixels (P) arranged on the same horizontal line can be connected to different sensing lines on a one-to-one basis. For example, the R subpixel (P), W subpixel (P), G subpixel (P), and B subpixel (P) forming a unit subpixel may each be connected one-to-one to different sensing lines.

Each subpixel (P) receives a high-potential driving voltage (EVDD) and a low-potential driving voltage (EVSS) from a power generator (not shown). The subpixel (P) of the present invention may include a circuit configuration suitable for an external compensation method. The external compensation method is a technology that senses the Vth of the driving TFT provided in the subpixels and corrects the input image data according to the sensed value. The TFTs constituting the subpixel P may be implemented as a p type, an n type, or a hybrid type combining the p type and the n type. Additionally, the semiconductor layer of the TFTs constituting the subpixel P may include amorphous silicon, polysilicon, or oxide.

Each subpixel (P) may include, but is not limited to, an OLED, a driving thin film transistor (TFT) (DT), a storage capacitor (Cst), a first switch TFT (ST1), and a second switch TFT (ST2). No. The connection configuration of the subpixel (P) can be modified in various ways.

The OLED includes an anode electrode connected to a source node (Ns), a cathode electrode connected to an input terminal of a low potential driving voltage (EVSS), and an organic compound layer located between the anode electrode and the cathode electrode.

The driving TFT (DT) controls the current input to the OLED according to the gate-source voltage (Vgs). The driving TFT (DT) has a gate electrode connected to the gate node (Ng), a drain electrode connected to the input terminal of the high potential driving voltage (EVDD), and a source electrode connected to the source node (Ns). The storage capacitor (Cst) is connected between the gate node (Ng) and the source node (Ns). The first switch TFT (ST1) applies the data voltage (Vdata) on the data line 140 to the gate node (Ng) in response to the gate signal (SCAN). The first switch TFT (ST1) includes a gate electrode connected to the gate line 150, a drain electrode connected to the data line 140, and a source electrode connected to the gate node (Ng). The second switch TFT (ST2) switches the current flow between the source node (Ns) and the sensing line 200 in response to the gate signal (SCAN). The second switch TFT (ST2) includes a gate electrode connected to the gate line 150, a drain electrode connected to the sensing line 200, and a source electrode connected to the source node Ns.

The sensing unit 122 connected to the subpixel P includes a sensing circuit SU including a reference voltage control switch, a sampling switch, and a sample and hold unit. The reference voltage control switch switches the electrical connection between the input terminal of the reference voltage (Vref) and the sensing line 200. The sampling switch switches the electrical connection between the sensing line 200 and the sample and hold unit.

Each subpixel (P) may operate differently during normal driving to write modulation data (RGBWm) to the display panel 100 and during sensing driving to measure the Vth shift of the subpixel (P). The modulation data (RGBWm) reflects a compensation value to compensate for the Vth shift of the subpixel (P). Sensing operation can be performed during a period when writing of modulation data (RGBWm) is stopped. For example, the sensing drive may be performed during the power-on sequence period immediately after the system power is applied, or may be performed during the power-off sequence period immediately after the system power is released. Sensing driving may be performed in a vertical blank period during an image display operation. The vertical blank period is a period in which modulation data (RGBWm) is not written, and is disposed between vertical active sections in which one frame of modulation data (RGBWm) is written.

Sensing driving may be performed by one operation of the data driving circuit 120 and the gate driving circuit 130 under the control of the timing controller 110. The operation of calculating and changing the compensation value to compensate for the change in the electrical characteristics of the subpixel (P) based on the sensing result and the operation of modulating the input image data (RGB) using the compensation value are performed in the timing controller 110. It can be done.

The data driving circuit 120 includes a plurality of digital-to-analog converters (hereinafter, DACs) (not shown) connected to each data line 140, a plurality of sensing units 122 connected to the sensing lines 200, and sensing The unit 122 includes an analog-to-digital converter (hereinafter referred to as an ADC) that digitally processes the output.

The DAC converts the modulated data (RGBWm) into a data voltage for image display according to the data timing control signal (DDC) applied from the timing controller 110 during normal driving and supplies it to the data lines 140. Additionally, the DAC generates a reference voltage (Vref) during normal driving and supplies it to the sensing lines 200.

Meanwhile, the DAC generates a data voltage for sensing according to the data timing control signal (DDC) applied from the timing controller 110 during sensing operation, supplies it to the data lines 140, and generates a reference voltage (Vref) for sensing. It can be supplied to lines 200.

The sensing unit 122 is connected to each sub-pixel (P) through the sensing line 200 and senses the electrical characteristics of the sub-pixel (P).

The ADC converts the sensing voltage input through the sensing unit 122 into sensing data (SD) and transmits it to the timing controller 110.

The gate driving circuit 130 may generate a gate signal SCAN based on the gate timing control signal GDC during normal driving and then supply the gate signal SCAN to the gate lines 150. The gate driving circuit 130 may generate a gate signal (SCAN) based on the gate timing control signal (GDC) during sensing operation and then supply the gate signal (SCAN) to the gate lines 150.

The timing controller 110 operates the data driving circuit 120 based on timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a dot clock signal (DCLK), and a data enable signal (DE). A data timing control signal (DDC) for controlling the timing and a gate timing control signal (GDC) for controlling the operation timing of the gate driving circuit 130 are generated. The timing controller 11 determines normal driving and sensing driving based on predetermined reference signals (driving power enable signal, vertical synchronization signal, data enable signal, etc.), and generates a data timing control signal (DDC) and a data timing control signal (DDC) for each drive. A gate timing control signal (GDC) can be generated.

The timing controller 110 compares the sensing data (SD) transmitted from the data driving circuit 120 during sensing operation with a previously stored initial sensing value. The initial sensing value may be obtained through sensing before a change in the electrical characteristics of the subpixel (P) occurs. The timing controller 110 may generate a compensation value that can compensate for the Vth shift of the subpixel (P) based on the difference between the sensing data (SD) and the initial sensing value. Then, the timing controller 110 modulates the input image data (RGB) for image display based on this compensation value and then transmits the modulated data (RGBWm) to the data driving circuit 120 during normal driving.

As described above, in the present invention, when implementing a target color that is a mixture of at least two or more pure colors, the black data of the subpixels that are driven relatively more and the subpixels that are driven relatively less are different from each other, so that the Vth shift level of the driving element is changed. can be minimized and abnormal luminance increase or decrease in luminance can be suppressed.

Furthermore, the present invention secures the output voltage margin of the data driving circuit by varying the black data according to the Vth shift level of the driving element according to changes over time, thereby solving the reliability problem due to insufficient output voltage margin of the data driving circuit.

Through the above-described content, those skilled in the art will be able to see that various changes and modifications can be made without departing from the technical idea of the present invention. Therefore, the technical scope of the present invention should not be limited to what is described in the detailed description of the specification, but should be defined by the scope of the patent claims.

11,21: Register 12,22: Timing controller
23: sensing unit 24: display panel

Claims (12)

A register storing color coordinates of pure color data; and
When implementing a target color in which at least two or more pure colors are mixed, driving pure colors or non-driving pure colors are distinguished by referring to the color coordinates of the pure color data, and among the driving pure colors and the non-driving pure colors, the driving pure color is predominantly reproduced. A timing controller that increases the black data of the second sub-pixel in which the non-driving pure color is predominantly reproduced compared to the black data of the sub-pixel,
The black data indicates data that can turn off the driving element included in each subpixel. According to claim 1,
The timing controller is,
When the non-driving pure color is reproduced in the first subpixel, the black data voltage to be applied to the gate electrode of the driving element of the first subpixel is the reference voltage to be applied to the source electrode of the driving element of the first subpixel. An organic light emitting display device that sets black data of the first subpixel to be lower. According to claim 1,
The timing controller is,
When the non-driving pure color is reproduced in the second subpixel, the black data voltage to be applied to the gate electrode of the driving element of the second subpixel is the reference voltage to be applied to the source electrode of the driving element of the second subpixel. An organic light emitting display device that sets black data of the second subpixel to be the same as . Current black data of the driving element, a first threshold value for the positive (+) shift amount of the threshold voltage of the driving element, a second threshold value for the (-) shift amount of the threshold voltage of the driving element, and black data of the driving element. a register storing a variable interval for;
A sensing unit that senses the current of the driving element according to a preset gate-source voltage; and
Based on the current sensing result of the driving element, the threshold voltage shift amount of the driving element is derived, and if the threshold voltage shift amount is greater than the first threshold, the black data of the driving element is converted into the current black within the variable section. a timing controller that lowers the black data of the driving device to a level lower than the current black data within the variable section when the threshold voltage shift amount is smaller than the second threshold;
The black data indicates data that can turn off the driving element. According to claim 4,
The timing controller is,
An organic light emitting display device wherein the black data of the driving element is lowered than the current black data within the variable section so that the black data voltage to be applied to the gate electrode of the driving element is lower than the black data voltage according to the current black data. According to claim 4,
The timing controller is,
An organic light emitting display device in which the black data of the driving element is raised above the current black data within the variable section so that the black data voltage to be applied to the gate electrode of the driving element is higher than the black data voltage according to the current black data. Storing color coordinates of pure color data; and
When implementing a target color in which at least two or more pure colors are mixed, driving pure colors or non-driving pure colors are distinguished by referring to the color coordinates of the pure color data, and among the driving pure colors and the non-driving pure colors, the driving pure color is predominantly reproduced. Raising the black data of the second sub-pixel in which the non-driving pure color is predominantly reproduced compared to the black data of the sub-pixel,
A method of driving an organic light emitting display device in which the black data indicates data that can turn off the driving element included in each subpixel. According to claim 7,
The step of increasing the black data of the second sub-pixel in which the non-driving pure color is predominantly reproduced compared to the black data of the first sub-pixel in which the driving pure color is predominantly reproduced includes:
When the non-driving pure color is reproduced in the first subpixel, the black data voltage to be applied to the gate electrode of the driving element of the first subpixel is the reference voltage to be applied to the source electrode of the driving element of the first subpixel. A method of driving an organic light emitting display device comprising setting black data of the first subpixel to be lower. According to claim 7,
The step of increasing the black data of the second sub-pixel in which the non-driving pure color is predominantly reproduced compared to the black data of the first sub-pixel in which the driving pure color is predominantly reproduced includes:
When the non-driving pure color is reproduced in the second subpixel, the black data voltage to be applied to the gate electrode of the driving element of the second subpixel is the reference voltage to be applied to the source electrode of the driving element of the second subpixel. A method of driving an organic light emitting display device comprising setting black data of the second subpixel to be the same as . Current black data of the driving element, a first threshold value for the positive (+) shift amount of the threshold voltage of the driving element, a second threshold value for the (-) shift amount of the threshold voltage of the driving element, and black data of the driving element. storing a variable section for;
Sensing the current of the driving element according to a preset gate-source voltage; and
Based on the current sensing result of the driving element, the threshold voltage shift amount of the driving element is derived, and if the threshold voltage shift amount is greater than the first threshold, the black data of the driving element is converted into the current black within the variable section. data, and when the threshold voltage shift amount is less than the second threshold, raising the black data of the driving element to be higher than the current black data within the variable section,
A method of driving an organic light emitting display device in which the black data indicates data that can turn off the driving element. According to claim 10,
By lowering the black data of the driving element than the current black data within the variable section,
A method of driving an organic light emitting display device in which the black data voltage to be applied to the gate electrode of the driving element is lower than the black data voltage according to the current black data. According to claim 10,
By raising the black data of the driving element above the current black data within the variable section,
A method of driving an organic light emitting display device in which the black data voltage to be applied to the gate electrode of the driving element is higher than the black data voltage according to Vgs corresponding to the current black data.