KR102135926B1 - Orgainc emitting diode display device and compensating method thereof - Google Patents

Abstract

The present invention relates to an OLED display device capable of reducing a boot time by reducing an initial compensation information loading time and an initial sensing time, and a compensation method thereof, wherein the initial compensation method of the present invention includes any one of a plurality of colors of each pixel. The color sub-color gain for the remaining sub-pixels and the reference compensation information for compensating for the characteristic of the reference sub-pixel are compared, indicating the characteristic correlation of each of the reference sub-pixels having a color and the remaining sub-pixels having different colors. A first step of loading from a volatile memory; Sensing compensation information for a reference sub-pixel is detected by sensing a characteristic of a reference sub-pixel among each pixel, and condition compensation for a reference sub-pixel according to an environmental condition is detected using reference compensation information and sensing compensation information for a reference sub-pixel A second step of detecting information; A third step of detecting condition compensation information for each remaining sub-pixel that is not sensed among each pixel, using condition compensation information and color gain for the reference sub-pixel sensed among each pixel; And a fourth step of detecting compensation information for compensating for the characteristics of each subpixel using reference compensation information and condition compensation information of each subpixel, and storing compensation information for each subpixel in a volatile memory.

Description

Organic light emitting diode display device and its compensation method {ORGAINC EMITTING DIODE DISPLAY DEVICE AND COMPENSATING METHOD THEREOF}

The present invention relates to an organic light emitting diode (OLED) display device, and more particularly, to an OLED display device capable of reducing boot time by reducing an initial compensation information loading time and an initial sensing time, and a compensation method thereof will be.

As a flat panel display that displays an image using digital data, a liquid crystal display (LCD) using a liquid crystal, an OLED display using an OLED, and an electrophoretic display using an electrophoretic particle (ElectroPhoretic Display; EPD) ) Etc. are typical.

Among them, the OLED display device is a self-luminous device that emits an organic light emitting layer by recombination of electrons and holes, and has high luminance, low driving voltage, and is capable of ultra-thinning, which is expected as a next-generation display device.

Each of the plurality of pixels (subpixels) constituting the OLED display device includes an OLED element composed of an organic light emitting layer between the anode and the cathode, and a pixel circuit that independently drives the OLED element. The pixel circuit includes at least a switching transistor and a storage capacitor and a driving transistor. The switching transistor charges the voltage corresponding to the data signal to the storage capacitor in response to the scan pulse, and the driving transistor controls the current supplied to the OLED device according to the voltage charged in the storage capacitor to adjust the amount of light emitted from the OLED device. The amount of light emitted from the OLED is proportional to the current supplied from the driving transistor.

OLED display devices have a problem of luminance non-uniformity between sub-pixels due to various reasons. For example, there is a difference in driving characteristics for each sub-pixel, such as threshold voltage (hereinafter, Vth) and mobility of the driving TFT due to process variation, and deterioration of the driving TFT or the OLED device as the driving time progresses. Due to the variable driving characteristics for each pixel due to the variable pixel current, a luminance non-uniformity problem occurs.

To solve this problem, the OLED display uses an external data compensation method that senses characteristic information of each subpixel and compensates video data using the sensing information.

For external data compensation, the OLED display needs a loading process to load initial compensation information previously stored in a non-volatile memory, NANDFlash Memory, into a volatile memory, a Double Data Rate (DDR) memory, when power is turned on. .

In addition, since the mobility of the oxide TFT varies with temperature and affects image quality, the OLED display device senses the mobility characteristic information of the driving TFT in each sub-pixel when the power is turned on, thereby presenting the initial compensation information. An initial temperature compensation process is needed to compensate for the temperature.

In order to prevent the user from being perceived by the loading process and the initial temperature compensation process, it is preferable to be performed at a boot time of less than 2 seconds before power is turned on and an image is displayed on the display panel.

However, as the resolution increases, such as UHD (Ultra High Definition), the size of the initial compensation information for each subpixel increases, so that the time for loading the initial compensation information increases, as well as the number of lines in the subpixel increases, thereby improving the characteristics of each subpixel. As the sensing time increases, the booting time increases or the normal screen is not displayed within a predetermined booting time, which causes inconvenience to the user.

The present invention has been devised to solve the above-mentioned problems, and an object to be solved by the present invention is to provide an OLED display device and a compensation method thereof that can reduce boot time by reducing the initial compensation information loading time and initial sensing time. Is to do.

In order to solve the above problems, a compensation method of an OLED display device according to an exemplary embodiment of the present invention is performed at boot time in an OLED display device including a plurality of subpixels, each of which constitutes a pixel array, having a different color. In the initial compensation method, the color for the remaining sub-pixels indicates a characteristic correlation between each of the sub-pixels having a color and a reference sub-pixel having one color among a plurality of colors of each pixel. A first step of loading each color gain and reference compensation information for compensating for the characteristics of the reference subpixel in a nonvolatile memory; Sensing compensation information for the reference sub-pixel is detected by sensing the characteristics of the reference sub-pixel among the pixels, and the reference according to environmental conditions is used by using the reference compensation information and the sensing compensation information for the reference sub-pixel. A second step of detecting condition compensation information for a subpixel; A third step of detecting condition compensation information for each remaining sub-pixel not sensed among the pixels, by using condition compensation information for the sensed reference sub-pixel among the pixels and the color gain; A fourth step of using the reference compensation information and the condition compensation information of each subpixel to detect compensation information for compensating for the characteristics of each subpixel and storing compensation information for each subpixel in a volatile memory. Includes.

An OLED display device according to an exemplary embodiment of the present invention includes: a display panel including a plurality of sub-pixels, each of which comprises a plurality of colors, each of pixels constituting a pixel array; A data driver driving the data line of the display panel and sensing a signal including the characteristic of each subpixel through the sensing line of the display panel to output sensing data; A gate driver driving a gate line of the display panel; A timing controller for controlling the driving of the data driver and the gate driver; The timing controller represents a characteristic correlation of each of the reference subpixels having one color among a plurality of colors of each pixel and the remaining subpixels having different colors, for initial compensation performed at boot time. Color gain for each remaining subpixel and reference compensation information for compensating the characteristics of the reference subpixel are loaded from a nonvolatile memory; Sensing compensation information for the reference sub-pixel is detected by sensing the characteristic of the reference sub-pixel among the pixels through the data driver, and using the reference compensation information and the sensing compensation information for the reference sub-pixel, the environment Detecting condition compensation information for the reference subpixel according to a condition; Detecting condition compensation information for each remaining sub-pixel not sensed among the pixels, by using the condition compensation information for the reference sub-pixel sensed among the pixels and the color gain; It characterized in that by using the reference compensation information and the condition compensation information of each sub-pixel, compensation information for compensating the characteristics of each sub-pixel is detected and the compensation information for each sub-pixel is stored in a volatile memory. .

The color gain is determined by a ratio between representative condition compensation information of the reference sub-pixel obtained through modeling and representative condition compensation information of each of the remaining sub-pixels, and is set in advance before shipment of the product together with the reference compensation information, so that the non-volatile It is stored in memory.

The representative condition compensation information is condition compensation information for each subpixel, or an average value of condition compensation information for each color in a block unit, a horizontal line unit, or a frame unit including a plurality of subpixels; The condition compensation information of each sub-pixel includes initial compensation information for compensating the initial mobility characteristic of each sub-pixel, and sensing compensation information for compensating the mobility characteristic of each sub-pixel sensed through the modeling. It is determined by the difference.

The reference subpixel is either one of the R/G/B subpixels in each pixel, or one of the R/G/B/W subpixels.

The timing controller detects condition compensation information for the reference subpixel as a difference between reference compensation information of the reference subpixel and sensing compensation information detected through sensing of the reference subpixel; Detecting condition compensation information of each of the remaining subpixels by multiplying the condition compensation information for the reference subpixel and the color gain; Combining the reference compensation information and the condition compensation information of each sub-pixel to detect compensation information for each sub-pixel; The reference compensation information, condition compensation information, and compensation information are compensation values for compensating the mobility characteristics of the corresponding subpixel.

The timing controller includes horizontal lines for loading the reference compensation information and color gain, detecting condition compensation information of the reference subpixel, detecting condition compensation information of the remaining subpixels, and detecting and storing compensation information of each subpixel. It is performed in units, and the above operation is repeated until the last horizontal line.

The OLED display device and the compensation method thereof according to the present invention have an initial loading time than when the initial compensation information for each of all sub-pixels is loaded by loading the reference compensation information for the reference sub-pixel of one color of each pixel in the loading step. Can be reduced.

In addition, since the OLED display device and the compensation method thereof according to the present invention only need to sense the characteristics of the reference subpixel among each pixel in the initial compensation step, the initial sensing time can be reduced than when all subpixels are sensed.

As a result, the OLED display device and its compensation method according to the present invention can reduce the boot time by reducing the loading time and the initial sensing time of the initial compensation information, or improve the compensation performance by securing an additional sensing time, or have a resolution. Even if it increases, there is an effect of showing the normal screen to the user by completing the initial compensation within the promised boot time.

1 and 2 are views comparing a prior art of the present invention and a sensing frame for initial compensation of an OLED display device according to the present invention.
FIG. 3 is a diagram illustrating distribution of first compensation information of an OLED display unit for each color frame to help understanding of the present invention.
FIG. 4 is a diagram showing normal distribution of second compensation information of an OLED display device for each color frame to help understanding of the present invention.
5 is a view showing temperature-compensated information for each color and predicted temperature-compensated information for each color sensed on a horizontal line according to a temperature change in the OLED display device according to the present invention.
6 is a block diagram illustrating an OLED display device according to an embodiment of the present invention.
7 is a flowchart illustrating a method of initial compensation of an OLED display device according to an exemplary embodiment of the present invention step by step.

1 and 2 are views comparing a prior art of the present invention and a sensing frame for initial compensation of an OLED display device according to the present invention, that is, a sensing time.

Due to the influence of ambient temperature, such as high temperature or low temperature, and the temperature of the object (user's palm, board, stove, etc.) that contacts the OLED display device, the OLED display device may vary in temperature or TFT In particular, the mobility characteristics of the oxide TFT are changed to have an effect on image quality. In order to compensate for the mobility characteristics due to external environmental conditions such as temperature or illuminance, the OLED display is in the initial booting stage that the user does not recognize when the power is turned on. Initial environmental compensation is performed to sense the mobility characteristics of the pixel and correct the preset initial compensation information.

The initial compensation information includes first initial compensation information for compensating the mobility characteristics of the driving TFT of each subpixel, and second initial compensation information for compensating the threshold voltage (Vth) characteristic of the driving TFT of each subpixel, , The first initial compensation information is corrected by the initial compensation.

In order to compensate the initial environment, in the prior art of the present invention, one frame is divided into R/W/G/B subframes as illustrated in FIG. 1, and subpixels of a corresponding color are sensed in each color subframe. The first initial compensation information for each pixel is corrected.

Specifically, a pixel array of an OLED display device is configured by sensing R subpixels in an R subframe, W subpixels in a W subframe, G subpixels in a G subframe, and B subpixels in a B subframe. The first initial compensation information for each subpixel is corrected by sensing all R/W/G/B subpixels.

The first initial compensation information for each subpixel is preset for each of the R/W/G/B subpixels of the pixel array in order to compensate for the initial characteristics of each subpixel before shipment of the product. It is loaded from NAND flash memory, which is non-volatile memory, to DDR memory, which is volatile memory. Of course, the second initial compensation information for each subpixel is also loaded in the booting step, but since the prior art and the present invention are the same, a description thereof will be omitted.

The OLED display device according to the prior art needs to load the first initial compensation information preset for each R/W/G/B subpixel in the booting phase, and senses the subpixels for each color in each R/W/G/B subframe. Since it has to be, there is a problem that the loading time and the sensing time increase as the resolution increases.

In order to solve the problems of the prior art, as shown in FIG. 2, the OLED display device according to the present invention has only one subframe of reference subpixels corresponding to one color among a plurality of colors of each pixel in an initial compensation step. Sensing from to detect the reference condition compensation information (Δα) according to the current external environmental conditions, and the condition compensation information (Δα) for each subpixel of the remaining color in each pixel is correlated with the reference subpixel and the corresponding subpixel It is predicted using the color gain (g) representing and the reference condition compensation information (Δα).

Here, the reference condition compensation information Δα is detected as a difference between the first sensing compensation information obtained by sensing the mobility characteristic of the reference subpixel in the current external environment and the first preset compensation information. The color gain g is preset using a ratio of reference subpixels through modeling and condition compensation information of the corresponding subpixels.

Accordingly, in the present invention, since only one reference subframe needs to be sensed at boot time, the sensing time can be shortened to 1/4 compared to the prior art sensing each of the R/W/G/B subframes. In addition, since the first initial compensation information is preset for only the reference subpixels corresponding to one color among a plurality of colors and stored in the NAND flash memory and loaded into the DDR memory, each of the R/W/G/B subpixels It is possible to shorten the loading time than the prior art loading the first initial compensation information for.

The reference subpixel may be determined as either R/W/G/B subpixels or R/G/B subpixels, but for convenience, the R subpixel among the R/W/G/B subpixels is a reference subpixel. Only the case used as a pixel will be described as an example.

For example, when the R subpixel is set as the reference subpixel, for initial compensation, only the R subpixels sense the mobility characteristic to detect the reference condition compensation information (Δα_R) according to the current external environment condition, and the sub of the remaining color. The condition compensation information (Δα_W, Δα_G, Δα_B) for each of the pixels is detected using color gain (g_W, g_G, g_B) and reference condition compensation information (Δα_R) indicating a correlation between a reference subpixel and another subpixel do.

The color gains (g_W, g_G, g_B) are representative condition compensation information for compensating the mobility characteristics of the reference subpixel through modeling using test images under a number of environmental conditions at the initial sensing stage before or after product shipment. Δα_R) and representative condition compensation information (Δα_W, Δα_G, Δα_B) to compensate for mobility characteristics of the remaining subpixels, that is, a proportional relationship may be detected and set in advance.

The color gain (g_W, g_G, g_B) settings compensate for the mobility characteristics of the R/W/G/B subpixels by having the mobility characteristics of the R/W/G/B subpixels similar or proportional to each other. It is possible because the compensation information (α) for each color for each has a similar distribution in each of the R/W/G/B subframes as shown in FIGS. 3 and 4. Also, as illustrated in FIG. 5, the amount of change according to the temperature of the compensation information α for each color, that is, the condition compensation information Δα is also possible because it has a proportional relationship for each color.

FIG. 3 is a diagram showing an α distribution for each color imaged in each of the R/W/G/B subframes, and FIG. 4 is a diagram showing the α distribution for each color schematically.

In FIG. 3, a value of low α is darkly represented, and a value of high α is brightly expressed.

3 and 4, the α distribution of the R subframe to compensate for the mobility characteristics of the R subpixels, the α distribution of the W subframe to compensate for the mobility characteristics of the W subpixels, and the G subpixel It can be seen that the α distribution of the G subframe to compensate for their mobility characteristics, the α distribution of the B subframe to compensate for the mobility characteristics of B subpixels, and the distribution shape of the normal distribution for each color are similar. , It shows the average value of the α distribution for each color.

FIG. 5 shows the color gain from the actual condition compensation information (Δα) detected from the sensing information of the Nth horizontal line and the condition compensation information of the reference subpixel when the hot plate is placed on the OLED display panel and the temperature distribution of the panel is different. It is a graph showing the prediction condition compensation information (Δα) predicted by using.

Referring to FIG. 5, when the temperature distribution of the panels is different due to hot plates of different temperatures as shown in (a), sensing compensation information sensed from R/W/G/B subpixels of the Nth horizontal line and The actual condition compensation information (Δα_R, Δα_W, Δα_G, Δα_B), which is the difference from the initial compensation information, differs for each color as shown in (b), but has a similar distribution with increasing condition compensation information (Δα) as the temperature increases. , It can be seen that the actual condition compensation information for each color (Δα_R, Δα_W, Δα_G, Δα_B) has a proportional relationship with each other.

In the Nth horizontal line, the average values (m_R, m_W, m_G, m_B) of the actual condition compensation information for each color (Δα_R, Δα_W, Δα_G, Δα_B) are respectively detected as representative values. W/G/ based on the R sub-pixel as follows by calculating the ratio for each of the average values (m_W, m_G, m_B) of the W/G/B sub-pixel based on the average value of the median R sub-pixel (m_R) Color gains (g_W, g_G, and g_B) for each of the B subpixels can be detected.

g_W = m_W/ m_R

g_G = m_G/ m_R

g_B = m_B/ m_R

For example, in FIG. 5(b), the reference gain of the R subpixel is 1, the color gain (g_W) of the W subpixel is 0.8, the color gain (g_G) of the G subpixel is 0.6, and the color of the B subpixel. It may be assumed that the gain g_B is detected as 1.2.

The color gains (g_W, g_G, g_B) detected using FIG. 5(b) are calculated with the actual condition compensation information (Δα_R) of the R subpixels, and the condition compensation information (Δα_W, Δα_G of each W/G/B subpixel) , Δα_B) is shown in FIG. 5(c), and it can be seen that the prediction information of FIG. 5(c) has an approximate value with the actual information of FIG. 5(b).

Accordingly, the OLED display device according to the present invention detects reference condition compensation information according to the current external environment condition by sensing only the reference subpixels in the initial compensation step, and the condition compensation information for each of the remaining color subpixels is the reference subpixel Since it can be detected using color gain and reference condition compensation information, which is a correlation between and the corresponding subpixel, loading time and sensing time of the initial compensation information can be reduced.

6 is a block diagram schematically illustrating an OLED display device according to an exemplary embodiment of the present invention.

The OLED display device shown in FIG. 6 includes a timing controller 10, a data driver 20, a gate driver 30, a gamma voltage generator 40, a display panel 50, a NAND flash memory 60, and a DDR memory ( 70).

In the nonvolatile memory NAND flash memory 60, initial compensation information and color gain including first reference compensation information and second initial compensation information together with various control information to be used in the timing controller 10 are preset and stored. . Various information stored in the NAND flash memory 60 is loaded into the volatile memory DDR memory 70 at boot time when the OLED display is powered on and used by the timing controller 10.

The initial compensation information is set in advance before shipment of the product, and the first initial compensation information for compensating the mobility characteristic of the reference subpixel among the R/G/B or R/W/G/B subpixels of each pixel is compensated based on It is included as information, and the first initial compensation information for sub-pixels of the remaining color is not included. In addition, the initial compensation information includes second initial compensation information for compensating the threshold voltage characteristic of each subpixel.

The color gain representing the correlation between each of the reference subpixels and subpixels of the remaining color is determined through pre-shipment modeling.

In modeling, the first initial compensation information for sensing and compensating for the initial mobility characteristics of each subpixel is detected for each R/W/G/B subpixel, and the mobility characteristics of each subpixel varied according to external environmental conditions The first sensing compensation information for sensing and compensating is detected for each R/W/G/B subpixel, and then the condition compensation information corresponding to the difference between the first initial compensation information and the first sensing compensation information is R/W /G/B Detect per subpixel. Subsequently, an average value of condition compensation information is detected as a representative value for each color in a block unit, a horizontal line unit, or a frame unit including a plurality of subpixels, and a ratio of each W/G/B average value is calculated based on the R average value. It is determined by the color gain of each W/G/B. Meanwhile, the color gain of each W/G/B may be determined by the ratio of the condition compensation information of the R subpixel and the condition compensation information of each W/G/B subpixel without calculating the average value.

The first reference compensation information and color gain loaded from the NAND flash memory 60 to the DDR memory 70 are used to detect and store the first compensation information of each subpixel by initial compensation, and the first of each subpixel is used. The compensation information is used when compensating the mobility characteristics of each subpixel, and the first compensation information can be updated and used through real-time compensation. The second initial compensation information is used when compensating the threshold voltage characteristic of each subpixel, and is updated and used as the second compensation information through real-time compensation.

The timing controller 10 generates a data control signal and a gate control signal that respectively control the driving timing of the data driver 20 and the gate driver 30 using a plurality of synchronous signals input from the outside, and the data driver 20 And output to the gate driver 30.

The timing controller 10 modulates an input image through various data modulation methods for improving image quality or reducing power consumption, and outputs the input image to the data driver 20.

The timing controller 10 uses the reference compensation information stored in the DDR memory 70 during the initial temperature compensation process to sense the mobility characteristic of the reference sub-pixel among each pixel and obtain sensing compensation information for compensating the sensed mobility characteristic. It detects and detects a difference between the sensing compensation information and the reference compensation information as reference condition compensation information. The timing controller 10 detects condition compensation information of each of the remaining subpixels except for the reference subpixel among the pixels by using the reference condition compensation information and color gain, and the reference compensation information using the condition compensation information of each subpixel Is corrected, and the correction result is stored in the DDR memory 70 as first compensation information of each subpixel.

The timing controller 10 compensates video data of each subpixel by using the first and second compensation information of each subpixel stored in the DDR memory 70. For example, the timing controller 10 compensates the video data by multiplying the video data and the second compensation information and adding the first compensation information.

The timing controller 10 updates the first and second compensation information to compensate for the mobility characteristic and the threshold voltage characteristic by sensing the characteristics of each subpixel through the data driver 20.

The timing controller 10 determines peak luminance according to image characteristic information, such as average picture level (APL) detected from the input image, and adjusts gamma high potential power according to the determined peak luminance to adjust gamma high potential. The power may be supplied to the gamma voltage generator 40.

The gamma voltage generation unit 40 generates a gamma voltage set including a plurality of gamma voltages having different levels and supplies it to the data driver 20. The gamma voltage generating unit 40 divides the gamma high potential power through a resistance string to generate and output a gamma voltage set including a plurality of gamma voltages. The gamma voltage generator 40 may be built in the data driver 20.

The data driver 20 converts digital data from the timing controller 10 into analog data signals in response to a data control signal from the timing controller 10 and supplies it to a plurality of data lines of the display panel 50. At this time, the data driver 20 subdivides the set of gamma voltages from the gamma voltage generator 40 into grayscale voltages corresponding to grayscale values of data, and then converts the digital data into analog data signals using the subdivided grayscale voltages. Convert to The data driver 20 is driven in a sensing mode for external compensation and a display mode for display driving under the control of the timing controller 10.

The data driver 20 is composed of at least one data drive IC, mounted on a circuit film such as a tape carrier package (TCP), a chip on film (COF), or a flexible print circuit (FPC), and the TAB on the display panel 50 (Tape Automatic Bonding) may be attached, or may be mounted on a non-display area of the display panel 50 by COG (Chip On Glass).

The gate driver 30 sequentially drives a plurality of gate lines of the display panel 50 in response to a gate control signal from the timing controller 10. The gate driver 30 supplies a scan pulse of a gate-on voltage in a corresponding scan period to each gate line in response to a gate control signal, and supplies a gate-off voltage in the remaining periods. The gate driver 30 may receive a gate control signal directly from the timing controller 10 or a gate control signal from the timing controller 10 via the data driver 20.

The gate driver 30 is composed of at least one gate drive IC and is mounted on a circuit film such as TCP, COF, FPC, etc., to be attached to the display panel 50 in a TAB method, or non-display of the display panel 50 in a COG method It can be mounted on an area. Alternatively, the gate driver 30 is formed in a non-display area of a TFT substrate together with a TFT array formed on a pixel array of the display panel 50, thereby forming a GIP (Gate In Panel) type embedded in the display panel 50. Can be.

The display panel 50 includes a matrix array of pixels. Each pixel of the pixel array implements a desired color with a combination of red (R), green (G), and blue (B) subpixels, and additionally includes a white (W) subpixel for luminance enhancement.

Each sub-pixel has an OLED element and a pixel circuit for driving the OLED element. The pixel circuit includes first and second switching TFTs ST1 and ST2 and a driving TFT DT and a storage capacitor Cst. Also, the pixel circuit includes first and second gate lines GLn1 and GLn2 that control the first and second switching TFTs ST1 and ST2, respectively, and data lines that supply data signals to the first switching TFT ST1 ( DLm), a reference line RLm supplying a reference voltage Vref to the second switching TFT ST2, an ELVDD line supplying a high potential power supply ELVDD to the driving TFT DT, and a cathode of the OLED. It is connected to the ELVSS line that supplies the low potential power supply (ELVSS).

The OLED is connected in series with the driving TFT (DT) between the ELVDD line and the ELVSS line. The OLED has an anode connected to the driving TFT (DT), a cathode connected to the ELVSS line, and a light-emitting layer between the anode and the cathode. The light emitting layer includes an electron injection layer, an electron transport layer, an organic light emitting layer, a hole transport layer, and a hole injection layer sequentially stacked between the cathode and the anode. In the OLED, when a positive bias is applied between the anode and the cathode, electrons from the cathode are supplied to the organic light emitting layer via the electron injection layer and the electron transport layer, and holes from the anode are supplied to the organic light emitting layer via the hole injection layer and the hole transport layer. do. Accordingly, the organic light emitting layer emits fluorescence or phosphorescence by recombination of supplied electrons and holes to generate light proportional to the amount of current.

The first switching TFT ST1 charges the storage capacitor Cst with a voltage corresponding to the data signal from the data line DL in response to the control of the first gate line GLn1. At this time, the second switching TFT ST2 supplies the reference voltage Vref from the reference line RLm to the connection node between the driving TFT DT and the OLED element in response to the control of the second gate line GLn2. . The driving TFT DT controls the current supplied to the OLED device according to the voltage charged in the storage capacitor Cst to control the amount of light emitted from the OLED device. Meanwhile, the second switching TFT ST2 may be used as a path for supplying the pixel current output according to the driving characteristics of the pixel circuit in the sensing mode to the reference line RLm.

In response to the control of the timing controller 10 in the sensing mode, the data driver 20 supplies the test data (pre-charge data) to the data line to drive the sub-pixel, and then the characteristics of the sub-pixel through the sensing channel. The sensing signal (voltage or current) included is sensed, and the sensing signal is converted into digital sensing data and transmitted to the timing controller 10. The sensing channel may be a reference line for supplying a reference voltage when driving each subpixel, a data line for supplying test data, or a readout line provided separately from them.

The timing controller 10 senses characteristic information of each subpixel by using the sensing data transmitted from the data driver 20 and detects first and second compensation information for compensating the characteristic information of the sensed subpixel. It is stored in the DDR memory 70.

For example, the timing controller 10 calculates the pixel current using the sensing data of each subpixel transmitted from the data driver 20, and uses a function to obtain the pixel current according to the Vth and K factors of the driving TFT. The Vth component and K factor component of each subpixel are sensed. The timing controller 10 determines the offset value for compensating Vth of each subpixel and stores the second compensation information in the DDR memory 70 as the second compensation information, and compensates the K factor of each subpixel. The gain value is determined and stored in the DDR memory 70 as the first compensation information to update the first compensation information.

The timing controller 10 drives the display panel 50 in a sensing mode for each display period before the shipment of the display device, the boot time at power on, the end time at power off, or the blank period of each frame, thereby subpixels through the data driver 20. Reward information is generated or updated whenever necessary by sensing the characteristics of.

7 is a flowchart illustrating a method of compensating for an initial temperature of an OLED display device according to an exemplary embodiment of the present invention.

The reference subpixel may be determined as either R/W/G/B subpixels or R/G/B subpixels, but for convenience, the R subpixel among the R/W/G/B subpixels is a reference subpixel. Only the case used as a pixel will be described as an example.

When the power of the OLED display is turned on in step 2 (S2), in step 4 (S4), the timing controller 10 receives initial compensation information, reference compensation information, and color gain for one horizontal line stored in the NAND flash memory 60. Is read and loaded into the DDR memory 70.

The reference compensation information is the first initial compensation information for compensating the mobility characteristics of each of the R sub-pixels, which is a reference sub-pixel, among the R/W/G/B sub-pixels, and the initial compensation information is R/W/G/B The second initial compensation information for compensating the threshold voltage characteristic of each subpixel. The color gain represents a proportional relationship between the condition compensation information of the reference R subpixel and the condition compensation information of each of the remaining W/G/B subpixels.

In step 6 (S6 ), the timing controller 10 senses the first sensing compensation information for compensating the mobility characteristic by sensing R subpixels of one horizontal line through the data driver 20.

In step 8 (S8), the timing controller 10 compares the first sensing compensation information with the first initial compensation information to detect reference condition compensation information Δα_R corresponding to the difference value.

In step 10 (S10), the timing controller 10 multiplies each of the reference condition compensation information (Δα_R) and the W/G/B color gains (g_W, g_G, g_B), thereby for each of the W/G/B subpixels. Condition compensation information (Δα_W, Δα_G, Δα_B) is detected.

In step 12 (S12), the timing controller 10 adds each of the condition compensation information (Δα_R, Δα_W, Δα_G, Δα_B) of the R/W/G/B subpixel to the reference compensation information α to calculate the external environmental conditions. The first compensation information (α'_R, α'_W, α'_G, α'_B) of each of the R/W/G/B subpixels whose mobility characteristics are corrected is calculated and stored in the DDR memory.

In step 14 (S14), the timing controller 10 repeats steps 4 (S4) to 14 (S14) in units of horizontal lines until the current horizontal line becomes the last line.

In step 14 (S14), if the current horizontal line is the last horizontal line, in the next step 16 (S16), the timing controller 10 turns on the display so that the normal screen is displayed on the display panel 50.

As described above, the OLED display device according to the present invention and its initial compensation method load the initial compensation information for each of all subpixels by loading the reference compensation information for the reference subpixel of one color of each pixel in the loading step The initial loading time can be reduced.

In addition, since the OLED display device and the initial compensation method according to the present invention only need to sense the characteristics of the reference subpixel among each pixel in the initial compensation step, the initial sensing time can be reduced than when all subpixels are sensed.

As a result, the OLED display device and its initial compensation method according to the present invention reduce the boot time by reducing the loading time and the initial sensing time of the initial compensation information, or improve the compensation performance by securing additional sensing time, or resolution Even if is increased, there is an effect of showing the normal screen to the user by completing the initial compensation within the promised boot time.

In the above, to illustrate and describe the technical spirit of the present invention in a specific embodiment, the present invention is not limited to the same configuration and operation as the specific embodiment as described above, and various modifications do not depart from the technical spirit of the present invention. It can be carried out within the scope. Therefore, such modifications should also be regarded as belonging to the scope of the present invention, and the scope of the present invention should be determined by the claims below.

10: timing controller 20: data driver
30: gate driver 40: gamma voltage generator
50: display panel 60: NAND flash memory
70: DDR memory

Claims (12)

In the initial compensation method performed at boot time in an OLED display device comprising a plurality of sub-pixels, each of which comprises a plurality of colors, each of which constitutes a pixel array,
A color gain for each color for the remaining subpixels indicating a characteristic correlation between a reference subpixel having one color among a plurality of colors of each pixel and each of the remaining subpixels having different colors, and the reference A first step of loading the reference compensation information for compensating for the characteristics of the subpixels from the nonvolatile memory;
Sensing compensation information for the reference sub-pixel is detected by sensing the characteristics of the reference sub-pixel among the pixels, and the reference according to environmental conditions is used by using the reference compensation information and the sensing compensation information for the reference sub-pixel. A second step of detecting condition compensation information for a subpixel;
A third step of detecting condition compensation information for each remaining sub-pixel not sensed among the pixels, by using condition compensation information for the sensed reference sub-pixel among the pixels and the color gain;
A fourth step of using the reference compensation information and the condition compensation information of each subpixel to detect compensation information for compensating for the characteristics of each subpixel and storing compensation information for each subpixel in a volatile memory. Compensation method of the OLED display comprising a. The method according to claim 1,
The color gain is determined by a ratio between representative condition compensation information of the reference sub-pixel obtained through modeling and representative condition compensation information of each of the remaining sub-pixels, and is set in advance before shipment of the product together with the reference compensation information, so that the non-volatile Compensation method of the OLED display device, characterized in that stored in the memory. The method according to claim 2,
The representative condition compensation information is condition compensation information for each subpixel, or an average value of condition compensation information for each color in a block unit, a horizontal line unit, or a frame unit including a plurality of subpixels;
The condition compensation information of each sub-pixel includes initial compensation information for compensating the initial mobility characteristic of each sub-pixel, and sensing compensation information for compensating the mobility characteristic of each sub-pixel sensed through the modeling. Compensation method of the OLED display device, characterized in that determined by the difference. The method according to claim 1,
The reference subpixel is any one of the R/G/B subpixels in each pixel, or one of the R/G/B/W subpixels. The method according to claim 1,
Condition compensation information for the reference subpixel is determined as a difference between reference compensation information of the reference subpixel and sensing compensation information detected through sensing of the reference subpixel in the second step;
In the third step, condition compensation information for each of the remaining subpixels is detected as a product of the condition compensation information for the reference subpixel and the color gain;
In the fourth step, compensation information for each subpixel is detected by adding the reference compensation information and the condition compensation information of each subpixel;
The reference compensation information, the condition compensation information, and the compensation information are compensation methods for compensating the mobility characteristics of the corresponding subpixel. The method according to claim 1,
The first to fourth steps are performed in units of horizontal lines and are repeated until the last horizontal line. A display panel including a plurality of subpixels each having a plurality of colors, each of which comprises a pixel array;
A data driver driving the data line of the display panel and sensing a signal including the characteristic of each subpixel through the sensing line of the display panel to output sensing data;
A gate driver driving a gate line of the display panel;
A timing controller for controlling the driving of the data driver and the gate driver;
The timing controller is for initial compensation performed at boot time,
A color gain for each color for the remaining subpixels indicating a characteristic correlation between a reference subpixel having one color among a plurality of colors of each pixel and each of the remaining subpixels having different colors, and the reference Reference compensation information for compensating for the characteristics of the subpixels is loaded from the nonvolatile memory;
Sensing compensation information for the reference sub-pixel is sensed by sensing the characteristic of the reference sub-pixel among the pixels through the data driver, and using the reference compensation information and the sensing compensation information for the reference sub-pixel, the environment Detecting condition compensation information for the reference subpixel according to a condition;
Using the condition compensation information for the reference sub-pixel sensed among the pixels and the color gain, condition compensation information for each remaining sub-pixel not sensed among the pixels is detected;
Using the reference compensation information and the condition compensation information of each sub-pixel, the compensation information for compensating the characteristics of each sub-pixel is detected and the compensation information for each sub-pixel is stored in a volatile memory. OLED display. The method according to claim 7,
The color gain is determined by a ratio between representative condition compensation information of the reference sub-pixel obtained through modeling and representative condition compensation information of each of the remaining sub-pixels, and is set in advance before shipment of the product together with the reference compensation information, so that the non-volatile OLED display device, characterized in that stored in the memory. The method according to claim 8,
The representative condition compensation information is condition compensation information for each subpixel, or an average value of condition compensation information for each color in a block unit, a horizontal line unit, or a frame unit including a plurality of subpixels;
The condition compensation information of each sub-pixel includes initial compensation information for compensating the initial mobility characteristic of each sub-pixel, and sensing compensation information for compensating the mobility characteristic of each sub-pixel sensed through the modeling. OLED display device characterized in that it is determined by the difference. The method according to claim 7,
The reference subpixel is any one of R/G/B subpixels in each pixel, or one of R/G/B/W subpixels. The method according to claim 7,
The timing controller
Detecting condition compensation information for the reference subpixel as a difference between reference compensation information of the reference subpixel and sensing compensation information detected through sensing of the reference subpixel;
Detecting condition compensation information of each of the remaining subpixels by multiplying the condition compensation information for the reference subpixel and the color gain;
Combining the reference compensation information and the condition compensation information of each sub-pixel to detect compensation information for each sub-pixel;
The reference compensation information, condition compensation information and compensation information are OLED display devices characterized in that the compensation value for compensating the mobility characteristics of the sub-pixel. The method according to claim 7,
The timing controller
Loading the reference compensation information and color gain, detecting condition compensation information of the reference subpixel, detecting condition compensation information of the remaining subpixels, and detecting and storing compensation information of each subpixel in units of horizontal lines. , Repeating the above operation until the last horizontal line.

Images