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EP-4047593-B1 - DISPLAY DEVICE

EP4047593B1EP 4047593 B1EP4047593 B1EP 4047593B1EP-4047593-B1

Inventors

  • KIM, JUNG TAEK
  • RYU, JAE WOO
  • BAIK, JOON SUK
  • LEE, SE KEUN

Dates

Publication Date
20260506
Application Date
20220218

Claims (5)

  1. A display device, comprising: a plurality of pixels (PXL); a power supply (420) configured to generate an initialization voltage (VINIT) to be supplied to a pixel to be sensed, hereinafter referred to as sensing pixel, among the plurality of pixels (PXL); an initialization voltage measurer (421) configured to measure a first value of the initialization voltage (VINIT) supplied to the sensing pixel during an active period of a frame period during which an image is displayed, and to measure a second value of the initialization voltage (VINIT) supplied to the sensing pixel during a vertical blank period of the frame period; a timing controller (410) configured to generate rewrite image data supplied to the sensing pixel during the vertical blank period, dependent on a difference between the first value and the second value of the initialization voltage (VINIT); and a data driver (310) configured to supply a data voltage to the pixels (PXL) based on image data supplied during the active period and to supply a rewrite data voltage to the sensing pixel based on the rewrite image data supplied during the vertical blank period, wherein the data voltage supplied to the pixels (PXL) during the active period is different from the rewrite data voltage supplied to the sensing pixel during the vertical blank period, and wherein the vertical blank period includes a sensing period, during which characteristics of the sensing pixel are sensed, and a data rewrite period after the sensing period, during which data rewrite period a previous image display state is reconstructed due to supply of the rewrite image data.
  2. The display device according to claim 1, wherein: the initialization voltage measurer (421) is provided with the initialization voltage (VNIT) from the power supply (420), and is configured to then convert a value of the initialization voltage (VNIT) into initialization voltage data; the initialization voltage measurer (421) is configured to provide the initialization voltage data to the timing controller; and the timing controller (410) is configured to determine at least one sensing control line used to perform sensing during the sensing period.
  3. The display device according to claim 2, wherein: the timing controller (410) is configured to store the image data that is supplied to the sensing pixel during the active period before the sensing period; the timing controller (410) stores the initialization voltage data applied to the sensing pixel during the active period as first initialization voltage data, and stores the initialization voltage data applied to the sensing pixel during the vertical blank period as second initialization voltage data; and the timing controller (410) calculates a correction grayscale value based on a difference between the first initialization voltage data and the second initialization voltage data, and the rewrite image data is generated from the image data applied to the plurality of pixels (PXL) during the active period and the correction grayscale value.
  4. A display device, comprising: a plurality of pixels (PXL); a timing controller (410) configured to predict an initialization voltage (VINIT) to be provided to a sensing pixel among the plurality of pixels (PXL) during an active period of a subsequent frame period during which an image is displayed and an initialization voltage (VINIT) to be provided to the sensing pixel during a vertical blank period of the subsequent frame period, and then generate rewrite image data by adding a correction grayscale value to image data (DAT) of the sensing pixel, wherein the rewrite image data is to be supplied to the sensing pixel; and a data driver (310) configured to supply a data voltage (DATA) to the plurality of pixels (PXL) during the active period and to supply a rewrite data voltage to the sensing pixel based on the rewrite image data during the vertical blank period, wherein the data voltage (DATA) supplied to the plurality of pixels (PXL) during the active period is different from the rewrite data voltage supplied to the sensing pixel during the vertical blank period, wherein the vertical blank period includes a sensing period during which characteristics of the sensing pixel are sensed and a data rewrite period after the sensing period, during which data rewrite period a previous image display state is reconstructed due to supply of the rewrite data voltage, wherein the timing controller (410) is configured to: determine at least one sensing control line used to perform sensing during the sensing period; store the image data (DAT) that is supplied to the plurality of pixels (PXL) during the active period before the sensing period; calculate a load accumulated up to the plurality of pixels (PXL) located on a previous horizontal line of the determined sensing control line (SSL) dependent on the image data (DAT) applied to the plurality of pixels (PXL) during the active period of one frame period, wherein the timing controller (410) comprises a load calculator (413b) configured to receive the image data (DAT) applied to the plurality of pixels (PXL) during the active period of a current frame and calculate the accumulated load up to the plurality of pixels (PXL) disposed on the previous horizontal line of the sensing pixel in a column direction in consideration of the provided image data (DAT); and predict initialization voltage data to be provided to the sensing pixel in the subsequent frame period based on information about a value of the load accumulated in the one frame period, wherein the previous image display state is reconstructed based on a difference between first initialization voltage data to be transferred to the sensing pixel during the active period of the subsequent frame and second initialization voltage data to be transferred to the sensing pixel after the sensing period of the subsequent frame, wherein the timing controller (410) is configured to predict the first initialization voltage data to be provided to the sensing pixel during the active period of the subsequent frame period and to predict the second initialization voltage data to be applied to the sensing pixel during the vertical blank period of the subsequent frame period, and the timing controller (410) calculates the correction grayscale value based on the difference between the first initialization voltage data and the second initialization voltage data.
  5. The display device according to claim 4, wherein the timing controller (410) comprises a correction grayscale calculator (414b) configured to calculate the correction grayscale value corresponding to the difference between the first initialization voltage data and the second initialization voltage data.

Description

1. Technical Field Embodiments of the present disclosure relate to a display device and more particularly to a display device that uses rewrite image data during a vertical blank period. 2. Discussion of Related Art A flat panel display (FPD) is an electronic viewing technology used to enable people to see content (e.g., still or moving images). An FPD is lighter, thinner, and uses less power than a traditional cathode ray tube (CRT) display. Examples of an FPD include a liquid crystal display device and an organic light emitting display device. A display panel of an FPD device includes pixels. Each of the pixels includes a light-emitting element and a driving transistor for supplying a driving current to the light-emitting element. Threshold voltage and mobility characteristics of the driving transistors included in the pixels may vary when these pixels degrade over time. Further, the light-emitting elements included in the pixels may also become degraded. Therefore, an external compensation circuit has been used in display devices to compensate for degradation of pixels. KR-A-2020/0079964 describes an organic light emitting diode display device capable of improving luminance uniformity by sensing a charging voltage ratio according to the position of each sub-pixel to accurately compensate for the difference in charging amount due to the voltage drop by position. A timing controller of the OLED display device charges a capacitor of each subpixel under the same conditions through a panel driver in a voltage drop sensing operation, and senses the charging voltage of each capacitor through a data line, compares a sensed voltage with a representative value and calculates a voltage drop compensation value to store the voltage drop compensation value in a memory, and compensates image data by applying the voltage drop compensation value stored in the memory in a display operation. KR-A-2020/0080783 describes an organic light emitting diode display device capable of preventing visibility of a sensing line in real-time by varying recovery data according to a frame rate, wherein a timing controller of the OLED display device according to one embodiment selects any one sensing line in the sensing period among the vertical blank periods of a frame through a panel driver, performs a sensing operation to sense the characteristics of each subpixel belonging to the selected sensing line, and performs a recovery operation of supplying recovery data to each subpixel of the sensing line in a recovery period after a sensing period, and the recovery data may be varied according to a frame rate change. US 2015/187268 A1 relates to an organic light emitting display capable of minimizing a luminance deviation between a display line, on which real-time sensing is performed, and a display line, on which the real-time sensing is not performed, when changes in electrical characteristic of a driving thin film transistor (TFT) are compensated in real time using an external compensation method. SUMMARY At least one embodiment of the present disclosure provides a display device, which suppresses a phenomenon in which a horizontal line is visually perceived when using an external compensation circuit. According to a first aspect, there is provided a display device as claimed in claim 1. According to a second aspect, there is provided a display device as claimed in claim 4. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically illustrating a display device according to an embodiment.FIG. 2 is a circuit diagram illustrating an example of a pixel included in the display device of FIG. 1.FIG. 3 is a circuit diagram illustrating an example of a data driver included in the display device of FIG. 1.FIG. 4 is a timing diagram illustrating an example of the operation of the pixel of FIG. 2.FIG. 5 is a timing diagram illustrating an example of the operation of the pixel of FIG. 2.FIG. 6 is a block diagram illustrating an example of a control board and a timing controller included in the display device of FIG. 1.FIG. 7 is a block diagram illustrating an example of the timing controller included in the display device of FIG. 1.FIG. 8 is a diagram illustrating an example of the operation of the display device of FIG. 1.FIG. 9 is a block diagram illustrating an example of the timing controller included in the display device of FIG. 1.FIG. 10 is a diagram illustrating the operation of a grayscale correction rate determiner of FIG. 9. DETAILED DESCRIPTION As the present disclosure allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. It will be understood that, although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For instance, a first element discussed below could be