Display with organic light-emitting diodes and method for their operation

Abstract

An organic light-emitting diode (OLED) display device according to an embodiment of the present disclosure may comprise: a display device configured to display an image and comprising a plurality of pixels, each of the plurality of pixels comprising a red subpixel, a green subpixel, a blue subpixel, and a white subpixel; and a processor configured to: obtain a first red data value, a first green data value, and a first blue data value based on the image; select one of a plurality of data combinations for a pixel that has the same brightness and color as the image; convert each of the first red data value, the first green data value, and the first blue data value into a second red data value, a second green data value, a second blue data value, and a first white data value according to the data combination;to apply the second red data value to the red subpixel; to apply the green subpixel to the second green data value; to apply the blue subpixel to the second blue data value; and to apply the first white data value to the white subpixel.

Description

[Technical area]

[0001] The present invention relates to an organic light-emitting diode display and a method of operating the same, and more particularly to preventing deterioration of the organic light-emitting diode display. [State of the art]

[0002] Recently, various types of display devices have emerged. Among them, organic light-emitting diode displays (hereinafter referred to as "OLED displays") are widely used. Because OLEDs are self-luminous devices, they consume less power and can be manufactured thinner than liquid crystal displays, which require a backlight. In addition, OLEDs have the advantages of a wide viewing angle and fast response time.

[0003] In a general organic light-emitting diode display, red (R), green (G), and blue (B) sub-pixels are configured as a unit pixel to display an image of different colors through the three sub-pixels.

[0004] When a still image is displayed for a long time, the cumulative light emission time between pixels is different, so there will be a difference in light emission ability between pixels at a certain time.

[0005] Therefore, if a still image is displayed for a long time and then switched to another image, the viewer sees an image in which the afterimage of the previous image is combined with a new image, which causes inconvenience to the user when viewing the image.

[0006] Conventionally, there is a technique of changing the image data of pixels that have a large cumulative light emission time to solve this problem, but this leads to the problem that a displayed image is distorted.

[0007] In addition, there is a conventional technique for reducing the degree of afterimage by using a low-pass filter (LPF), but this also has the problem of distorting the displayed image. [Revelation][Technical Problem]

[0008] The object of the present disclosure is to prevent burn-in of a display panel by using a combination of RGBW data that maintains the same color and brightness as an original image.

[0009] The object of the present disclosure is to prevent a rapid change in brightness at the boundary between a still image and a background image by using a combination of RGBW data that maintains the same color and brightness as the original image. [Technical solution]

[0010] An organic light-emitting diode (OLED) display device according to an embodiment of the present disclosure may include: a display device configured to display an image and including a plurality of pixels, each of the plurality of pixels including a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel; and a processor configured to: obtain a first red data value, a first green data value, and a first blue data value based on the image; select one of a plurality of data combinations for a pixel having the same brightness and color as the image; convert each of the first red data value, the first green data value, and the first blue data value into a second red data value, a second green data value, a second blue data value, and a first white data value according to the data combination;apply the second red data value to the red subpixel; apply the second green data value to the green subpixel; apply the second blue data value to the blue subpixel; and apply the first white data value to the white subpixel.

[0011] A method of operating an organic light-emitting diode (OLED) display device comprising a display panel configured to display an image and comprising a plurality of pixels, each of the plurality of pixels comprising a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel, according to an embodiment of the present disclosure, may include: obtaining a first red data value, a first green data value, and a first blue data value based on the image; selecting one of a plurality of data combinations for a pixel having the same brightness and color as the image; converting each of the first red data value, the first green data value, and the first blue data value into a second red data value, a second green data value, a second blue data value, and a first white data value according to the data combination;Applying the second red data value to the red subpixel; applying the second green data value to the green subpixel; applying the second blue data value to the blue subpixel; and applying the first white data value to the white subpixel.; [Beneficial effects]

[0012] According to various embodiments of the present disclosure, the burn-in phenomenon is prevented and the lifetime of a subpixel is increased by distributing load so that a particular subpixel is not overloaded.

[0013] Furthermore, according to various embodiments of the present disclosure, afterimage and degradation of certain subpixels in an OLED device can be prevented without changing the brightness and color of the pixel.

[0014] In addition, a sudden change in brightness at the boundary between the still image and the background image can be prevented, which improves the viewing experience. [Description of the drawings]

[0015] They show: Fig. 1 is a diagram for describing the configuration of an organic light-emitting diode display device according to an embodiment of the present invention; Fig. 2 is a flowchart illustrating a method for operating an organic light-emitting diode display device according to an embodiment of the present invention; Fig. 3 is a flowchart illustrating a method for operating an organic light-emitting diode display device according to an embodiment of the present invention; Fig. 4 is a diagram for describing a conventional method for extracting data values ​​of a W subpixel; Fig. 5 is a diagram describing a plurality of data combinations in which color and brightness of an image output by a unit pixel are not damaged according to an embodiment of the present disclosure; Fig. 6 is a diagram for describing a method for selecting one of a plurality of data combinations for R / G / B / W subpixels according to an embodiment of the present disclosure; Fig. 7A is a diagram describing that the brightness of subpixels at the boundary between a content image and a background image changes rapidly due to an afterimage in an existing display device; Fig. 7B is a diagram for describing a method for gradually changing the brightness of subpixels at a boundary between a content image and a background image according to an embodiment of the present disclosure; and Fig. 8 and Fig. 9 diagrams describing the brightness gradation of subpixels at the boundary between a still image and a background image. [Best operating mode]

[0016] Embodiments related to the present disclosure will be described in detail below with reference to the drawings. The suffixes "module" and "unit" for components used in the following description are assigned or interchanged for convenience in writing the description and do not have any specific meanings or roles in and of themselves.

[0017] Fig. 1 is a diagram for describing the configuration of an organic light-emitting diode display device according to an embodiment of the present invention.

[0018] As in Fig. 1, the organic light-emitting diode display device 100 includes a display panel 110, a 4-color data converter 120 (4-color data conversion unit), a timing controller 130, a gate driver 140, a data driver 150, a memory 160, and a processor 170.

[0019] The display panel 110 may include a plurality of subpixels (SPs). A plurality of subpixels may be formed in a pixel area defined by a plurality of gate lines GL and a plurality of data lines DL that cross each other.

[0020] In the display panel 110, a plurality of drive power lines PL are formed in parallel to each of the plurality of data lines DL to supply a drive voltage.

[0021] Each of the plurality of subpixels may be a red subpixel, a green subpixel, a blue subpixel, or a white subpixel.

[0022] A unit pixel displaying an image may include a red subpixel, a green subpixel, a blue subpixel, and a white subpixel.

[0023] Each of the plurality of sub-pixels SP may comprise an organic light-emitting diode (OLED) and a pixel circuit PC.

[0024] The OLED is connected between the pixel circuit PC and the control line PL2 and emits light proportional to the amount of data current supplied by the pixel circuit PC, thereby emitting light of a predetermined color.

[0025] For this purpose, the OLED may include an anode electrode (or pixel electrode) connected to the pixel circuit PC, a cathode electrode (or reflection electrode) connected to the drive power supply line PL2, and a light-emitting cell formed between the anode electrode and the cathode electrode and emitting light of any color among red, green, blue, and white.

[0026] The light-emitting cell may have a hole transport layer / organic light-emitting layer / electron transport layer structure or a hole injection layer / hole transport layer / organic light-emitting layer / electron transport layer / electron injection layer structure.

[0027] The light-emitting cell can additionally be provided with a functional layer that improves at least one of the light efficiency and lifetime of the organic light-emitting layer.

[0028] The pixel circuit PC supplies a data current corresponding to a data voltage Vdata supplied to a data line DL from the data driver 150 to the OLED in response to a gate signal GS having a gate-on voltage level supplied to a gate line GL from the gate driver 140.

[0029] The data voltage Vdata has a voltage value at which the degradation characteristics of the OLED are compensated.

[0030] The pixel circuit PC includes a switching transistor, a driving transistor, and at least one capacitor formed on a substrate by a thin film transistor formation process.

[0031] The switching transistor and the driver transistor can be an a-Si TFT, a poly-Si TFT, an oxide TFT or an organic TFT.

[0032] The switching transistor can supply the data voltage Vdata applied to the data line DL to the gate electrode of the driver transistor according to the gate signal of the gate-on voltage level applied to the gate line.

[0033] The driver transistor is turned on depending on the gate-source voltage including the data voltage Vdata supplied by the switching transistor, thereby controlling the current flowing from the driver voltage line PL1 to the OLED.

[0034] The 4-color data converter 120 can generate data provided to the unit pixel of the display panel 110 based on a time synchronization signal (TSS) input from an external system location (not shown) or a graphics card (not shown) and 3-color input data (Ri, Gi, and Bi).

[0035] The 4-color data converter 120 can generate four-color data (R, G, B, and W) in red, green, blue, and white, which are respectively supplied to a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel constituting a unit pixel, based on the time synchronization signal TSS and the three-color input data Ri, Gi, and Bi.

[0036] The generated four-color data (R, G, B, and W) can be forwarded to the timing controller 130.

[0037] The 4-color data converter 120 may also include a filter (not shown). The filter may remove noise from the 3-color input data.

[0038] For example, the filter can perform grayscale filtering of red, green, and blue data to remove noise from tricolor input data. The filter can filter one or more of the red, green, and blue data.

[0039] The 4-color data converter 120 may be included in the timing control device 130.

[0040] The timing controller 130 may control the driving of the gate driver 140 and the data driver 150 based on a time synchronization signal TSS input from an external system location (not shown) or a graphics card (not shown).

[0041] The timing controller 130 may generate a gate control signal GCS and a data control signal DCS based on a timing synchronization signal TSS, such as a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a dot clock.

[0042] The timing controller 130 may control the drive timing of the gate driver 140 via the gate control signal GCS and control the drive timing of the data driver 150 via the data control signal DCS so as to be synchronized therewith.

[0043] The timing controller 130 may accumulate the data (R, G, B, and W) of each sub-pixel SP supplied from the 4-color data converter 120 in each sub-pixel SP unit for each frame or accumulation period set to a constant period and store it in the memory 160.

[0044] The gate driver 140 may generate a gate signal GS corresponding to the display order of the image based on the gate control signal GCS supplied from the timing controller 130, and supply the generated gate signal GS to the corresponding gate line GL.

[0045] The gate driver 140 is formed in the form of a plurality of integrated circuits (ICs) or directly on the substrate of the display device 100 along with a process of forming a transistor for each sub-pixel (SP) and may be connected to one side or both sides of a plurality of gate lines (GLs).

[0046] The data driver 150 can receive pixel data DATA and a data control signal DCS from the timing controller 130.

[0047] The data driver 150 may receive a plurality of reference gamma voltages from an external reference gamma voltage supply (not shown).

[0048] The data driver 150 can convert the pixel data DATA into an analog data voltage Vdata based on the data control signal DCS and a plurality of reference gamma voltages.

[0049] The data driver 150 can supply the converted data voltage Vdata to the data line DL of the corresponding sub-pixel SP. Accordingly, each unit pixel constituting the display panel 110 emits light from the corresponding organic light-emitting element OLED through the data current based on the data voltage Vdata supplied to each sub-pixel SP, thereby displaying a predetermined image.

[0050] For each unit pixel, only three subpixels may be addressed, including one white subpixel among the red, green, blue, and white subpixels, or all four subpixels may be addressed.

[0051] The data driver 150 may be implemented in the form of a plurality of integrated circuits (ICs) and connected to one side and / or both sides of the data line DL.

[0052] The timing controller 130 can control the operation of the 4-color data converter 120, the gate driver 140, the data driver 150, and the memory 160.

[0053] Since the Fig. 1 is merely an embodiment of the present invention, some of the illustrated components may be integrated, added, or omitted depending on the specifications of the organic light-emitting diode display device 100 actually implemented.

[0054] For example, the 4-color data converter 120 and the timing controller 130 are configured as a single control unit, or the 4-color data converter 120, the timing controller 130, the gate driver 140, and the data driver 150 may be included in a single control unit (not shown).

[0055] The processor 170 can control the overall operation of the organic light-emitting diode display device 100.

[0056] The processor 170 can control the operation of the display panel 110, the 4-color data converter 120, the timing controller 130, the gate driver 140, the data driver 150, and the memory 160.

[0057] In another example, the processor 170 is not provided separately, and a configuration including a 4-color data converter 120, a timing controller 130, a gate driver 140, and a data driver 150 may be a processor.

[0058] Fig. 2A shows a diagram describing the formation of afterimages, and Fig. 2B and Fig. 2C show diagrams for describing problems in a prior art afterimage prevention method.

[0059] As in Fig. 2A, the display device 10 displays a content image 210 on the display panel 11.

[0060] A single pixel forming the content image 210 has a first RGB data combination 211.

[0061] When the content image 210 is converted into a white image after a long display, an afterimage 230 corresponding to the content image 210 is displayed on the display panel 11.

[0062] This is because the light emitting ability of the pixel is affected by the cumulative light emission amount of the pixel due to the material limitation of the pixel.

[0063] This means that when a still image is displayed for a long period of time, the cumulative amount of light emission between pixels is different, resulting in a difference in the light emission capability between pixels. Therefore, when a still image is displayed for a long time and then switched to another image, the user sees an image where the afterimage of the previous still image is combined with the new image, which impairs viewing.

[0064] Fig. Figure 2B is a diagram illustrating a conventional technique for modifying data of an input image source to solve the afterimage problem described above.

[0065] The display device 20 calculates and stores the cumulative light emission time (or accumulated emission amount) for each pixel. The display device 20 manages the cumulative light emission time of each pixel.

[0066] When there is a difference in the cumulative light emission time between pixels, the display device makes 20 pixels with a large cumulative light emission time darker than the brightness of the original image data, or makes pixels with a small cumulative light emission time brighter than the brightness of the original image data.

[0067] However, since this method distorts the original image 250 and displays the distorted image 270 on the display panel 21, the user's viewing experience is still disturbed.

[0068] Fig. Figure 2C shows a diagram describing a conventional technique in which an input image source is passed through a low-pass filter (LPF) to solve the afterimage problem.

[0069] That is, the display device 23 smoothly changes the brightness distribution of neighboring pixels by passing the LPF through the input image source.

[0070] However, this method also blurs the original image 280 and displays the distorted image 290 on the display panel 25, which further impairs the user's viewing experience.

[0071] The following is a summary of the Fig. 3 describes a method for operating an OLED display device according to an embodiment of the present invention.

[0072] In addition, the following description will be made in connection with the configuration of the OLED display device 100 described with reference to Fig. 1 is described.

[0073] Hereinafter, the organic light-emitting diode display device 100 is also referred to as a display device.

[0074] Fig. 3 shows a flowchart illustrating a method for operating a display device with organic light-emitting diodes according to an embodiment of the present invention.

[0075] According to Fig. 3, the processor 170 of the display device 100 may determine the cumulative light emission time of each of the R / G / B / W sub-pixels included in the unit pixel (S301).

[0076] The processor 170 may calculate the time during which current is supplied to each subpixel as the emission time of the subpixel. The processor 170 may calculate the cumulative light emission time of each subpixel up to the current time by counting the time during which each subpixel is supplied with current.

[0077] The processor 170 may calculate the cumulative light emission time of each sub-pixel as the time required for the data driver 150 to supply the data voltage Vdata to each sub-pixel.

[0078] The cumulative light emission time can be converted into a normalized cumulative emission amount.

[0079] The processor 170 may calculate a first cumulative light emission time of the sub-pixel R (red), a second cumulative light emission time of the sub-pixel G (green), a third cumulative light emission time of the sub-pixel B (blue), and a fourth cumulative light emission time of the sub-pixel W (white), which constitute a unit pixel.

[0080] The processor 170 may store the first accumulated light emission time, the second accumulated light emission time, the third accumulated light emission time, and the fourth accumulated light emission time in the memory 160.

[0081] The processor 170 may calculate the first cumulative light emission time, the second cumulative light emission time, the third cumulative light emission time, and the fourth cumulative light emission time at regular time intervals and store the calculated results in the memory 160.

[0082] The memory 160 may be an image frame memory for storing image frames.

[0083] The processor 170 may select one of a plurality of data combinations for the R / G / B / W sub-pixels based on the acquired cumulative light emission times (S303).

[0084] Each of the plurality of data combinations has the same color and brightness of the input image (or original image) input to the display panel 110, but the R data value (the data value of the R sub-pixel), the G data value (the data value of the G sub-pixel), the B data value (data value of the B sub-pixel), and the W data value (data value of the W sub-pixel) may be different from each other.

[0085] The W data value can be automatically determined from the R data value, the G data value and the B data value.

[0086] A combination of a plurality of data of a unit image output by a unit pixel is described.

[0087] Fig. Fig. 4 is a diagram describing a conventional method for extracting the data value of a W subpixel, and Fig. 5 is a diagram describing a plurality of data combinations in which color and brightness of an image output by a unit pixel are not damaged according to an embodiment of the present disclosure.

[0088] With reference to part (a) in Fig. 4 shows the R data value, the G data value and the B data value.

[0089] As described in part (b) of Fig. 4, the W data value is determined as the smallest G data value among the R data value, the G data value and the B data value.

[0090] Thereafter, each of the remaining R data, G data, and B data is determined as a value obtained by subtracting the W data from the original data as described in part (c) of Fig. 4 shown.

[0091] That is, the R / G / B / W data values ​​of 4 colors can be calculated from the R / G / B data values ​​of 3 colors as follows [Equation 1]. WOUT=MIN[RGBIN] RGBOUT=RGBIN−WOUT

[0092] In part (a) of Fig. 5 are the same R-data value, G-data value and B-data value as in part (a) of Fig. 4 shown.

[0093] If the person referred to in part (b) of Fig. 4 certain W data value to a slightly smaller value as in part (b) of Fig. 5, each of the R data value, the G data value and the B data value is slightly larger than part (b) of Fig. 4.

[0094] At this time, the brightness and color of the unit pixel are not changed. This is because the reduced brightness of the W subpixel is compensated by the brightness of the R / G / B subpixels.

[0095] In addition, the sum of the R data value, the G data value and the B data value can be replaced by the W data value, so that the color of the unit pixel is not changed compared to the original image.

[0096] The number of R / G / B / W data combinations that do not affect the brightness and color of the original image output via the unit pixels can be equal to the W data value.

[0097] With reference to part (c) of Fig. 5, if the W data value is greater than that in part (b) of Fig. 5, each of the R data value, the G data value and the B data value is slightly larger than part (b) of Fig. 5.

[0098] In this way, a variety of data combinations can be generated that do not affect the brightness and color of the original image.

[0099] Fig. 3 is described again.

[0100] The processor 170 may calculate difference values ​​of two cumulative light emission times between the first cumulative light emission time of the R sub-pixel, the second cumulative light emission time of the G sub-pixel, the third cumulative light emission time of the B sub-pixel, and the fourth cumulative light emission time of the W sub-pixel.

[0101] In one embodiment, processor 170 may select a data combination that minimizes the sum of the difference values ​​while maintaining the color and brightness of the input image (or original image).

[0102] In another embodiment, when the difference value between the cumulative light emission times between the two sub-pixels is greater than or equal to a predetermined value, the processor 170 may select one of a plurality of data combinations to reduce the difference value to less than a predetermined value while maintaining the color and brightness of the original image.

[0103] Accordingly, the lifetime of the individual subpixels is similar, so that an afterimage can be avoided.

[0104] In another embodiment, if there is a subpixel that exceeds a predetermined time among the first cumulative light emission time of the R subpixel, the second cumulative light emission time of the G subpixel, the third cumulative light emission time of the B subpixel, and the fourth cumulative light emission time of the W subpixel, the processor 170 may select a data combination to reduce the data value of the corresponding subpixel and increase the data value of each of the remaining subpixels while maintaining the color and brightness of the original image.

[0105] If two or more subpixels exceed a preset time, a data combination can be selected in which the data values ​​of the corresponding subpixels are reduced and the data values ​​of the remaining subpixels are increased.

[0106] In another embodiment, if there is a subpixel whose duration is shorter than a predetermined time among the first cumulative light emission time of the R subpixel, the second cumulative light emission time of the G subpixel, the third cumulative light emission time of the B subpixel, and the fourth cumulative light emission time of the W subpixel, the processor 170 may select a data combination to increase the data value of the corresponding subpixel and decrease the data value of each of the remaining subpixels while maintaining the color and brightness of the original image.

[0107] If there are two or more subpixels for less than a preset time, a data combination can be selected in which the data values ​​of the corresponding subpixels are increased and the data values ​​of the remaining subpixels are decreased.

[0108] In another embodiment, processor 170 may randomly select one of a plurality of data combinations while maintaining the color and brightness of the original image. In this case, unlike other embodiments, no separate operation is required, and the load on processor 170 may be reduced.

[0109] In another embodiment, processor 170 may select, from a plurality of data combinations, a data combination that reduces the data value of subpixel B and increases the data values ​​of the remaining subpixels while preserving the color and brightness of the original image. Since the lifetime of subpixel B is generally shorter than that of the other subpixels, a data combination may be selected in a direction that maximizes the lifetime of subpixel B.

[0110] In addition, step S303 may be performed by the 4-color data converter 120 instead of the processor 170.

[0111] That is, the 4-color data converter 120 can select one of a plurality of data combinations for the R / G / B / W sub-pixels based on the acquired cumulative light emission times.

[0112] The 4-color data converter 120 can convert any of the R / G / B data values ​​into any of the R / G / B / W data values ​​corresponding to the selected data combination.

[0113] The processor 170 may apply all data corresponding to the selected data combination to each of the R / G / B / W subpixels (S305).

[0114] The processor 170 may control the 4-color data converter 120 to supply the converted R / G / B / W data values ​​to the timing controller 130.

[0115] The processor 170 may convert the first red data value, the first green data value, and the first blue data value into the second red data value, the second green data value, and the second blue data value corresponding to the selected data combination and a first white data value based on the input image.

[0116] The processor 170 may apply the second red data value to the red subpixel, the second green data value to the green subpixel, the second blue data value to the blue subpixel, or the first white data value to the white subpixel.

[0117] The timing controller 130 may supply pixel data including R / G / B / W data values ​​to the data driver 150.

[0118] The data driver 150 can convert pixel data into an analog data voltage and supply the converted data voltage to a data line of a corresponding sub-pixel.

[0119] Accordingly, the unit pixel constituting the display panel 110 can display a predetermined image when the OLED emits light through the data current based on the data voltage supplied to each sub-pixel.

[0120] Fig. 6 is a diagram for describing a method for selecting one of a plurality of data combinations for R / G / B / W subpixels according to an embodiment of the present disclosure.

[0121] With reference to Fig. 6 shows a data combination including data values ​​for each of the R subpixel, G subpixel, B subpixel, and W subpixel that form the unit pixel of the image 600.

[0122] That is, the number of a plurality of data combinations may be N to obtain the brightness and color of the unit image displayed by the unit pixel.

[0123] The processor 170 can select one of a plurality of data combinations that preserves the brightness and color of the original image.

[0124] In one embodiment, the processor 170 may select a data combination that dims the brightness of a subpixel having the largest cumulative light emission time among a plurality of data combinations that preserve the brightness and color of the original image.

[0125] That is, the processor 170 can select, from a plurality of data combinations that preserve the brightness and color of the original image, a data combination that reduces the brightness of a subpixel with the largest cumulative light emission time.

[0126] In another embodiment, the processor 170 may select a data combination that brightens the brightness of a subpixel having the smallest cumulative light emission time among a plurality of data combinations that preserve the brightness and color of the original image.

[0127] That is, the processor 170 may select a data combination that increases the brightness of a subpixel with the smallest cumulative light emission time among a plurality of data combinations while maintaining the brightness and color of the original image.

[0128] In another embodiment, the processor 170 may randomly select a data combination from a plurality of data combinations while preserving the brightness and color of the original image.

[0129] As described above, according to an embodiment of the present disclosure, a data combination may be selected taking into account the cumulative light emission time of each sub-pixel.

[0130] This not only prevents distortion of the original image, but also balances the lifetime of the subpixels that make up the unit pixels, thus preventing afterimages.

[0131] Whether the embodiment of Fig. 3 is applicable to the display device can also be determined by the following method.

[0132] 1-1. The display device 100 displays a test still image.

[0133] 1-2. The user then selects a specific pixel from a variety of pixels that display the test still image.

[0134] 1-3. The user observes the brightness of each of the R / G / B / W subpixels that make up a particular pixel using a magnifying glass or microscope.

[0135] 1-4. After a certain time (e.g., 5 minutes) has elapsed, observe whether the brightness of each of the R / G / B / W subpixels constituting a particular pixel changes.

[0136] 1-5. When the brightness of each of the R / G / B / W sub-pixels constituting a particular pixel is changed during the display of the test still image, it can be considered that an embodiment of the present disclosure in which the selected data combination is applied to the R / G / B / W sub-pixels by selecting one of a plurality of data combinations that maintains the brightness and color of the original image has been selected.

[0137] Whether the embodiment of Fig. 3 is applied to the display device can be determined by the following method.

[0138] 2-1. The display device 100 creates a first test still image and a second test still image. The first test still image and the second test still image each include partial images that have the same brightness and color.

[0139] 2-2. The first test pattern is displayed and remains for a specified time.

[0140] 2-3. The brightness of each R / G / B / W subpixel of the partial image mentioned in 2-1 is observed with a magnifying glass or a microscope.

[0141] 2-4. The second test freeze frame is displayed and retained for a specified time.

[0142] 2-5. The brightness of each R / G / B / W subpixel of the partial image mentioned in 2-1 is observed with a magnifying glass or a microscope.

[0143] 2-6. When the brightness of each of the R / G / B / W subpixels observed in 2-3 and 2-5 is different from each other, it can be considered that the embodiment of the present disclosure is applied.

[0144] Fig. 7A is a diagram describing that the brightness of subpixels at the boundary between a content image and a background image changes rapidly due to afterimages in an existing display device, and Fig. 7B is a diagram describing a process of gradually changing the brightness of subpixels at a boundary between a content image and a background image according to an embodiment of the present disclosure.

[0145] In Fig. 7A, the conventional display device 10 displays a rectangular image 711 having a rectangular shape and a white background image 712.

[0146] After a certain time has elapsed, the rectangular image 711 disappears, and an afterimage 713 of the rectangular image 711 is displayed.

[0147] Likewise, with reference to Fig. 7A shows a first pixel distribution diagram 721 representing data of each sub-pixel with respect to the horizontal position (horizontal coordinate) of the display device 10 in the form of a bar chart, and a second pixel distribution diagram 723 representing data of each sub-pixel with respect to the horizontal position of the display device 10 in the form of a line.

[0148] From the first pixel distribution diagram 721 and the second pixel distribution diagram 723, it can be seen that the brightness of the sub-pixels changes rapidly starting from the boundary position (x1) between the rectangular image 711 and the background image 712.

[0149] Accordingly, it can be seen that the boundary of the generated afterimage 713 is equally sharp.

[0150] Since, as described above, according to the prior art, the brightness of the subpixels changes rapidly from the boundary position between the rectangular image 711 and the background image 713, the viewer perceives the afterimage 713 just as strongly.

[0151] In Fig. 7B, the display device 100 according to an embodiment of the present disclosure displays a rectangular image 711 having a rectangular shape and a white background image 712.

[0152] After a certain time has elapsed, the rectangular image 711 disappears and an afterimage 715 of the rectangular image 711 is displayed.

[0153] When a still image, such as the rectangular image 711, is captured, the processor 170 may select from a plurality of data combinations a data combination that smooths a brightness change of each of the R / G / B / W subpixels.

[0154] The multitude of data combinations may be combinations in which the brightness and color of the pixel remain the same, but the data values ​​of the subpixels differ from each other.

[0155] The processor 170 may select such a data combination that the brightness of the subpixels is smoothed from the pixels of the square image 711 to the pixels of the background image 712.

[0156] The processor 170 determines a gradient representing the degree of reduction of the data value of the corresponding subpixel based on the difference between the data value of the subpixel (one of the RGBW subpixels) constituting the pixel in the center of the rectangular image 711 and the data value of the subpixel constituting the pixel at the boundary position. The selected subpixel may have the smallest data value.

[0157] The processor 170 decreases the data value of the selected subpixel toward the position of the background image 712 based on the center of the rectangular image 711 according to the obtained gradient and adjusts the data values ​​of the remaining subpixels accordingly.

[0158] Accordingly, the brightness distribution between corresponding subpixels of neighboring pixels can be smoothed.

[0159] According to one embodiment of the present disclosure, Fig. 7B shows a third pixel distribution diagram 731 representing data of each sub-pixel with respect to the horizontal position (horizontal coordinate) of the display device 100 in the form of a bar chart, and a fourth pixel distribution diagram 733 representing data of each sub-pixel with respect to the horizontal position of the device 100 in the form of a line.

[0160] From the third pixel distribution diagram 731 and the fourth pixel distribution diagram 733, it can be seen that the brightness of the sub-pixels, starting from the boundary position (x1) between the rectangular image 711 and the background image 712, differs from the first pixel distribution diagram 721 and the second pixel distribution diagram 723 by Fig. 7A changes more smoothly.

[0161] Accordingly, it can be seen that the edge of the generated afterimage 715 is also smooth.

[0162] As described above, according to an embodiment of the present disclosure, the afterimage 713 is perceived less strongly by the viewer because the brightness of the subpixels gradually changes from the boundary position between the rectangular image 711 and the background image 712.

[0163] Fig. 8 and Fig. 9 show diagrams describing the brightness gradation of subpixels at the boundary between a still image and a background image.

[0164] With reference to part (a) and part (b) of Fig. 8, the display device 100 displays a test still image 800.

[0165] After a certain time (e.g. 5 minutes) has elapsed, the user observes with a magnifying glass or a microscope the brightness of a certain sub-pixel along a horizontal solid line in part (a) or a vertical solid line in part (b) of Fig. 8.

[0166] When the brightness of a certain sub-pixel of each pixel gradually changes along a horizontal solid line or a vertical solid line, an embodiment in which a data combination that smooths the change in the brightness of each of the R / G / B / W sub-pixels among a plurality of data combinations is applied while maintaining the brightness and color of the pixel can be considered.

[0167] Next, Fig. 9 described.

[0168] 3-1. As in Fig. 9, the display device 100 displays a monochrome image pattern 900 on the entire screen.

[0169] 3-2. A user observes a first pixel at a first point 901, a second pixel at a second point 902, and a third pixel at a third point 903 of the image pattern 900 using a magnifying glass or a microscope.

[0170] 3-3. Even if the first pixel, the second pixel, and the third pixel have the same brightness and color, the embodiment of the disclosure can be considered to be applied when the brightness of the R / G / B / W sub-pixels constituting the first pixel, the second pixel, and the third pixel are different.

[0171] As in Fig. 9, the display device 100 may also select a data combination having a similar distribution of the R / G / B / W data values ​​considering the color of the neighboring pixel when displaying the single-color image pattern 900.

[0172] According to one embodiment of the present invention, the method described above can be implemented as processor-readable code in a medium on which a program is recorded. Examples of processor-readable media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like.

Claims

[1] An organic light-emitting diode (OLED) display device comprising: a display panel configured to display an image and comprising a plurality of pixels, each of the plurality of pixels comprising a red subpixel, a green subpixel, a blue subpixel, and a white subpixel; and a processor configured to: obtain a first red data value, a first green data value and a first blue data value based on the image; selecting one of a plurality of data combinations for a pixel that has the same brightness and color as the image; converting each of the first red data value, the first green data value, and the first blue data value into a second red data value, a second green data value, a second blue data value, and a first white data value according to the data combination; apply the second red data value to the red subpixel; apply the second green data value to the green subpixel; apply the second blue data value to the blue subpixel; and apply the first white data value to the white subpixel. [2] The OLED display device of claim 1, wherein the processor is further configured to: to obtain a first cumulative light emission time of the red sub-pixel, a second cumulative light emission time of the green sub-pixel, a third cumulative light emission time of the blue sub-pixel, and a fourth cumulative light emission time of the white sub-pixel; and select a data combination based on the first accumulated light emission time, the second accumulated light emission time, the third accumulated light emission time, and the fourth accumulated light emission time. [3] The OLED display device of claim 2, wherein the processor is configured to: to select the data combination to increase the brightness of a sub-pixel having the smallest cumulative light emission time among the first cumulative light emission time, the second cumulative light emission time, the third cumulative light emission time, and the fourth cumulative light emission time. [4] The OLED display device of claim 2, wherein the processor is configured to: select the data combination to reduce the brightness of a sub-pixel having the largest accumulated light emission time among the first accumulated light emission time, the second accumulated light emission time, the third accumulated light emission time, and the fourth accumulated light emission time. [5] The OLED display device of claim 2, wherein the processor is further configured to: Calculate difference values ​​between two cumulative light emission times among the first cumulative light emission time, the second cumulative light emission time, the third cumulative light emission time and the fourth cumulative light emission time; to select the data combination in such a way that the sum of the difference values ​​is minimized. [6] The OLED display device of claim 2, wherein the processor is further configured to: calculate a difference value between two cumulative light emission times among the first cumulative light emission time, the second cumulative light emission time, the third cumulative light emission time and the fourth cumulative light emission time; select the data combination to reduce the difference value to less than the predetermined value when the calculated difference value is greater than or equal to the predetermined value. [7] The OLED display device of claim 1, wherein the processor is further configured to: to randomly select any one of the multitude of data combinations. [8] The OLED display device according to claim 1, wherein the display panel is configured to display a still image and a background image, the processor is configured to select the data combination such that the brightness of the subpixel is smoothed from the pixel of the still image to the pixel of the background image. [9] A method of operating an organic light-emitting diode (OLED) display device comprising a display panel configured to display an image and comprising a plurality of pixels, each of the plurality of pixels comprising a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel, comprising: Obtaining a first red data value, a first green data value, and a first blue data value based on the image; Selecting one of a plurality of data combinations for a pixel that has the same brightness and color as the image; Converting each of the first red data value, the first green data value, and the first blue data value into a second red data value, a second green data value, a second blue data value, and a first white data value according to the data combination; Apply the second red data value to the red subpixel; Apply the second green data value to the green subpixel; Applying the second blue data value to the blue subpixel; and Apply the first white data value to the white subpixel. [10] The method of claim 9, further comprising: Obtaining a first cumulative light emission time of the red sub-pixel, a second cumulative light emission time of the green sub-pixel, a third cumulative light emission time of the blue sub-pixel and a fourth cumulative light emission time of the white sub-pixel, wherein the step of selecting the data combination comprises: Selecting a data combination based on the first accumulated light emission time, the second accumulated light emission time, the third accumulated light emission time, and the fourth accumulated light emission time. [11] The method of claim 10, wherein the step of selecting the data combination comprises: Selecting the data combination to increase the brightness of a sub-pixel having the smallest cumulative light emission time among the first cumulative light emission time, the second cumulative light emission time, the third cumulative light emission time, and the fourth cumulative light emission time. [12] The method of claim 10, wherein the step of selecting the data combination comprises: Selecting the data combination to reduce the brightness of a sub-pixel having the largest accumulated light emission time among the first accumulated light emission time, the second accumulated light emission time, the third accumulated light emission time, and the fourth accumulated light emission time. [13] The method of claim 10, further comprising: Calculating difference values ​​between two cumulative light emission times among the first cumulative light emission time, the second cumulative light emission time, the third cumulative light emission time and the fourth cumulative light emission time, wherein the step of selecting the data combination comprises: Selecting the data combinations such that the sum of the difference values ​​is minimized. [14] The method of claim 10, further comprising: Calculating a difference value between two cumulative light emission times among the first cumulative light emission time, the second cumulative light emission time, the third cumulative light emission time and the fourth cumulative light emission time, wherein the step of selecting the data combination comprises: Selecting the data combination to reduce the difference value to less than the predetermined value when the calculated difference value is greater than or equal to the predetermined value. [15] The method of claim 9, wherein the step of selecting the data combination comprises: randomly selecting any one of the plurality of data combinations.

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