DISPLAY DEVICE WITH A SCREEN SAVER CONTROL DEVICE AND METHOD FOR OPERATING A DISPLAY DEVICE WITH A SCREEN SAVER CONTROL DEVICE

Description

1. Technical Field

[0001] Embodiments of the present inventive concept relate to a display device. More specifically, embodiments of the present inventive concept relate to a screen saver controller, a display device including the same and a method of operating a display device including the same.2. Discussion of Related Art

[0002] A display device may include a display panel and a display panel driver. The display panel includes pixels. Image data input to the pixels causes display of an image. The display panel may be connected to the display panel driver through gate lines and data lines. The display panel driver may include a gate driver that provides a gate signal to the display panel through the gate lines, a data driver that provides a data voltage to the display panel through the data lines, and a timing controller that controls the gate driver and the data driver.

[0003] The display device may operate in a screen saver mode when a predetermined condition is satisfied. When the display device operates in the screen saver mode, the display device may output a black image to the display panel or perform an operation of lowering the luminance of the display panel. A conventional display device operates in the screen saver mode without considering load data of the display panel and life data of the display panel. Accordingly, even when the screen saver mode is operated, an afterimage is perceivable on the conventional display device, and the lifespan of the display panel is reduced.

[0004] United States Patent Application Publication US2016 / 0217731 A1 describes an organic light-emitting diode (OLED) display and method of adjusting luminance of a logo region of an image displayed on the same are disclosed. In one example, the OLED display includes a display panel configured to display an image including a logo region. The display panel includes a plurality of red, green, and blue color pixels. The OLED display also includes a display driver configured to drive the display panel and reduce the luminance of blue color light emitted from blue color pixels located in the logo region.

[0005] In United States Patent Application Publication US2019 / 0213953A1 describes a luminance control circuit of a display device that includes a target luminance gain calculator calculating a target luminance gain based on an average luminance of a first image signal when the first image signal is determined to be a still image, an output luminance gain calculator calculating an output luminance gain based on a previous output luminance gain of a previous frame and the target luminance gain of a present frame, and a luminance scaler outputting a second image signal obtained by changing a luminance of the first image signal based on the output luminance gain.SUMMARY

[0006] Various aspects and embodiments of the present invention are set out in the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Illustrative, non-limiting embodiments of the inventive concept will be more clearly understood from the following detailed description in conjunction with the accompanying drawings, in which: FIG 1 is a block diagram illustrating a display device according to an embodiment of the present inventive concept; FIGS. 2a and 2b are diagrams illustrating an example of a plurality of panel blocks included in a display panel of FIG 1; FIG 3 is a block diagram illustrating a screen saver controller included in a display device of FIG 1; FIGS. 4a and 4b are graphs illustrating a change in a start time of a screen saver mode and a change in a minimum luminance of the screen saver mode when load data of the display panel is increased; FIGS. 5a and 5b are graphs illustrating a change in a start time of a screen saver mode and a change in a minimum luminance of the screen saver mode when life data of the display panel is increased; FIG 6 is a graph illustrating a change in luminance of an image displayed on the display panel when the screen saver mode is operated; FIG 7 is a diagram illustrating an example of a change in luminance of an image displayed on the display panel for each period of FIG 6; FIG 8 is a graph illustrating a change in pixel life according to a driving time of the display device when a screen saver data generator generates screen saver data based on gain data; FIG 9 is a flowchart illustrating an example in which the screen saver mode is executed in the display device 10; FIG 10 is a block diagram illustrating an electronic device according to an embodiment of the present inventive concept; and FIG 11 is a diagram illustrating an example in which the electronic device of FIG 10 is implemented as a smartphone. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0008] Hereinafter, embodiments of the present inventive concept will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components will be omitted.

[0009] FIG 1 is a block diagram illustrating a display device 10 according to an embodiment of the present inventive concept. FIGS. 2a and 2b are diagrams illustrating an example of a plurality of panel blocks included in a display panel 100 of FIG 1.

[0010] Referring to FIGS. 1 to 2b, the display device 10 includes a display panel 100 and a display panel driver 120 (e.g., a driver circuit). The display panel driver 120 may include a timing controller 200 (e.g., a control circuit), a gate driver 300 (e.g., a driver circuit), a gamma reference voltage generator 400, and a data driver 500 (e.g., driver circuit). The display panel driver 120 further includes a screen saver controller 600 (e.g., control circuit).

[0011] The display panel 100 may include a display region for displaying an image and a peripheral region disposed adjacent to the display region. For example, the peripheral region may surround the display region.

[0012] The display panel 100 includes pixels P, and display an image corresponding to input image data by using the pixels P. The gate lines GL may extend in a first direction D1, and the data lines DL may extend in a second direction D2 intersecting the first direction D1.

[0013] The display panel 100 includes a plurality of panel blocks. In other words, the display panel 100 is divided into a plurality of panel blocks. Each of the panel blocks includes a plurality of pixels P Each of the panel blocks may include n by m pixels, where n and m are real numbers greater than one. In one embodiment, each of the panel blocks is a large panel block 110 (e.g., PBL). In an embodiment, the large panel block 110 includes 240*120 pixels P. In an embodiment, the display device 10 calculates load data and life data in units of the large panel block 110. In another embodiment, each of the panel blocks is a small panel block 120 (e.g., PBS). In an embodiment, the small panel block 120 includes 8*8 pixels. In an embodiment, the display device 10 calculates load data and life data in a units of the small panel block 120. The small panel block 120 has less pixels or a smaller area than the large panel block 110. The large panel block 110 is not limited to being sized to include 240x120 pixels, and the small panel bock 120 is not limited to being sized to include 8x8 pixels. For example, the large panel block 110 may be larger or smaller than 240x120 pixels, and the smaller panel block 120 may be larger or smaller than 8x8 pixels.

[0014] The timing controller 200 may receive input image data IMG and an input control signal CONT from an external device (not shown). For example, the input image data IMG received from the external device may include red image data, green image data, and blue image data. According to an embodiment, the input image data IMG further includes white image data. In another example, the input image data IMG includes magenta image data, yellow image data, and / or cyan image data. The input control signal CONT may include at least one of a master clock signal, a data enable signal, a vertical sync signal, and a horizontal sync signal.

[0015] The timing controller 200 may generate a first control signal CONT1, a second control signal CONT2, a third control signal CONT3, and a data signal DATA based on the input image data IMG and the input control signal CONT.

[0016] The timing controller 200 may generate the first control signal CONT1 for controlling an operation of the gate driver 300 based on the input control signal CONT to output the first control signal CONT1 to the gate driver 300. The first control signal CONT1 may include a vertical start signal and a gate clock signal.

[0017] The timing controller 200 may generate the second control signal CONT2 for controlling an operation of the data driver 500 based on the input control signal CONT to output the second control signal CONT2 to the data driver 500. The second control signal CONT2 may include a horizontal start signal and a load signal.

[0018] The timing controller 200 may generate the data signal DATA based on the input image data IMG The timing controller 200 may output the generated data signal DATA to the data driver 500.

[0019] The timing controller 200 may generate the third control signal CONT3 for controlling an operation of the gamma reference voltage generator 400 based on the input control signal CONT. The timing controller 200 may output the generated third control signal CONT3 to the gamma reference voltage generator 400.

[0020] The gate driver 300 may generate gate signals for driving gate lines GL in response to the first control signal CONT1 received from the timing controller 200. The gate driver 300 may output the generated gate signals to the gate lines GL. For example, the gate driver 300 may sequentially output the gate signals to the gate lines GL. According to an embodiment, the gate driver 300 is mounted on a periphery of the display panel.

[0021] The gamma reference voltage generator 400 may generate a gamma reference voltage VGREF in response to the third control signal CONT3 received from the timing controller 200. The gamma reference voltage generator 400 may provide the generated gamma reference voltage VGREF to the data driver 500. The gamma reference voltage VGREF provided to the data driver 500 may have a value corresponding to each data signal DATA. According to an embodiment, the gamma reference voltage generator 400 is disposed in the timing controller 200 or is disposed in the data driver 500.

[0022] The data driver 500 may receive the second control signal CONT2 and the data signal DATA from the timing controller 200, and receive the gamma reference voltage VGREF from the gamma reference voltage generator 400. The data driver 500 may convert the data signal DATA having a digital format into a data voltage having an analog format by using the gamma reference voltage VGREF. The data driver 500 may output the data voltage to the data lines DL.

[0023] The screen saver controller 600 receives the input image data IMG from the timing controller 200. In an embodiment, the screen saver controller 600 generates screen saver data SSD based on the input image data IMG and outputs the screen saver data SSD to the timing controller 200. In another embodiment, the screen saver controller 600 receives the data signal DATA from the timing controller 200 and generates the screen saver data SSD based on the data signal DATA. The arrangement of the screen saver controller 600 of FIG 1 is an example according to one embodiment of the present inventive concept. According to another embodiment, the screen saver controller 600 is disposed inside the timing controller 200 so as to be a part of the timing controller 200. According to embodiment shown in FIG 1, the screen saver controller 600 is disposed outside the timing controller 200 to interact data with the timing controller 200. A detailed operation of the screen saver controller 600 will be described with reference to FIGS. 3 to 5.

[0024] FIG 3 is a block diagram illustrating an embodiment of the screen saver controller 600 included in the display device 10 of FIG 1. FIGS. 4a and 4b are graphs illustrating a change in a start time TSS of a screen saver mode and a change in a minimum luminance LM of the screen saver mode when load data LD of the display panel 100 is increased. FIGS. 5a and 5b are graphs illustrating a change in a start time TSS of a screen saver mode and a change in a minimum luminance LM of the screen saver mode when life data of the display panel 100 is increased.

[0025] Referring to FIGS. 1 to 3, the screen saver controller 600 includes a load calculator / generator (e.g., a logic circuit) 610 for generating load data LD, a life calculator / generator 620 (e.g., logic circuit) for generating life data AD, an operation data generator 630 (e.g., a logic circuit) for generating operation data including gain data GD, and a screen saver data generator 640 (e.g., a logic circuit) for generating screen saver data SSD. The foregoing generators / calculator may also be referred to as means for performing the associated functions. The screen saver controller 600 may determine whether to operate in the screen saver mode based on the input image data IMG In an embodiment, the screen saver controller 600 determines to operate in the screen saver mode when the input image data IMG corresponds to a static or non-moving image or a portion of the input image data IMG has an intensity that exceeds a certain threshold. When the screen saver mode is operated in the display device 10, the timing controller 200 may adjust the luminance of the display panel 100 based on the screen saver data SSD.

[0026] The load calculator 610 generates load data LD of each of the panel blocks included in the display panel 100 based on the input image data IMG In an embodiment, the load data LD of a given panel block among the panel blocks is calculated from an average intensity of intensities of the pixels of the given panel block. In an embodiment, the load data LD of the given panel block is generated from an average voltage of data voltages applied to the pixels of the given panel block. Specifically, the load calculator 610 may store load data LD corresponding to the input image data IMG in the form of a lookup table LUT. The load calculator 610 may select the load data LD corresponding to the input image data IMG from the lookup table, and calculate the load data LD of each of the panel blocks to transmit the load data LD to the operation data generator 630. The lookup table may be any storage device in which the load data LD corresponding to the input image data IMG is stored. For example, the load calculator 610 may calculate the load data LD in units of the large panel block 110. The large panel block 110 may include 240* 120 pixels P. The load calculator 610 may select the load data LD corresponding to the input image data IMG from the lookup table, and calculate the load data LD in units of the large panel block 110 to transmit the load data LD to the operation data generator 630. In another example, the load calculator 610 may calculate the load data LD in units of the small panel block 120. The small panel block 120 may include 8*8 pixels. The load calculator 610 may select the load data LD corresponding to the input image data IMG from the lookup table, and calculate the load data LD in units of the small panel block 120 to transmit the load data LD to the operation data generator 630.

[0027] The life calculator 620 generates life data AD of each of the panel blocks based on a deterioration stress value accumulated in the display panel 100. In an embodiment, the life calculator 620 accumulates deterioration stress values for each of the panel blocks representing a deterioration stress level of each of the panel blocks to generate an accumulated value and stores the accumulated value into a nonvolatile memory device of the display device 19, and generates the life data AD according to the accumulated value. In an embodiment, the accumulating sums the deterioration stress values. In this way, the life data AD is a sum of deterioration stress values for the panel block. In another embodiment, the accumulating averages the deterioration stress values. In this way, the life data AD is an average of deterioration stress values for the panel block. When calculating the life data AD, the life calculator 620 may consider several factors that cause the deterioration stress. For example, the life calculator 620 may accumulate the deterioration stress values in consideration of temperature data, position data of the panel block, number of light emissions and period of the light emission, and generate the life data AD of each of the panel blocks based on the factors. For example, the life calculator 620 may apply different weights to the deterioration stress values during the accumulating based on the factors. In an embodiment, an increase in a value of the life data AD signifies that the deterioration stress applied to the panel block is large or exceeds a certain threshold. In other words, the increase in the value of the life data AD may signify that an accumulated usage amount of the panel blocks is large. In an embodiment, the life calculator 620 calculates the life data AD in units of the large panel block 110. The large panel block 110 may include 240*120 pixels P. The life calculator 620 may accumulate the deterioration stress values to generate an accumulated deterioration stress value and store the accumulated deterioration stress value of the display panel 100 into a nonvolatile memory device, calculate the life data AD in a unit of the large panel block 110 according to the accumulated deterioration stress value and transmit the life data AD to the operation data generator 630. In another example, the life calculator 620 calculates the life data AD in units of the small panel block 120. The small panel block 120 may include 8*8 pixels. The life calculator 620 accumulates the deterioration stress values to generate an accumulated deterioration stress value and may store the accumulated deterioration stress value of the display panel 100 into a nonvolatile memory device, calculate the life data AD in a unit of the small panel block 120 according to the accumulated deterioration stress value and transmit the life data AD to the operation data generator 630.

[0028] Referring to FIGS. 3 and 4a to 5b, the operation data generator 630 generates gain data GD based on the load data LD and the life data AD. The operation data generator 630 may generate the gain data GD, and transmit the gain data GD to the screen saver data generator 640. In an embodiment, the operation data generator 630 generates start time gain data for adjusting the start time TSS of the screen saver mode according to the load data LD and the life data AD. The operation data generator 630 may generate minimum luminance gain data for adjusting the minimum luminance LM of the screen saver mode according to the load data LD and the life data AD. For example, the operation data generator 630 generates the start time gain data for allowing the screen saver mode to be adjusted to start earlier as the load data LD increases. The operation data generator 630 may transmit the start time gain data to the screen saver data generator 640. In addition, the operation data generator 630 may generate the minimum luminance gain data for adjusting the minimum luminance of the screen saver mode to be lower as the load data LD increases. The operation data generator 630 may transmit the minimum luminance gain data to the screen saver data generator 640. In another example, the operation data generator 630 generates the start time gain data for allowing the screen saver mode to be adjusted to start earlier as the life data AD increases. The operation data generator 630 may transmit the start time gain data to the screen saver data generator 640. In an embodiment, the operation data generator 630 generates the minimum luminance gain data for adjusting the minimum luminance of the screen saver mode to be lower as the life data AD increases. The operation data generator 630 may transmit the minimum luminance gain data to the screen saver data generator 640.

[0029] In an example not falling under the scope of the invention as claimed, the operation data generator 630 generates the start time gain data and the minimum luminance gain data based on the load data LD of a first panel block having a greatest load data LD among the panel blocks and the life data AD of the first panel block. In an embodiment, an overall intensity of each of the panel blocks is determined, and the panel block with the highest intensity has the greatest load data LD. Specifically, the operation data generator 630 may select the first panel block having the greatest load data LD among the panel blocks based on the load data LD. The operation data generator 630 may generate start time gain data for adjusting the start time TSS of the screen saver mode based on the life data AD of the first panel block. In addition, the operation data generator 630 may generate minimum luminance gain data for adjusting the minimum luminance LM of the screen saver mode based on the life data AD of the first panel block. For example, the start time TSS of the screen saver mode of the display device 10 may be earlier in proportion to the life data AD of the first panel block. In another example, the minimum luminance LM of the screen saver mode of the display device 10 may be lowered in proportion to the life data AD of the first panel block. For example, when a value of the current life data AD relative to the prior life data indicate a 10% decrease in the life of a panel block, the minimum luminance LM could be decreased by 10%.

[0030] In an example example not falling under the scope of the invention as claimed, the operation data generator 630 generates the start time gain data and the minimum luminance gain data based on the load data LD of a first panel block having a greatest load data LD among the panel blocks, and the life data AD of a second panel block having the greatest life data AD among the panel blocks. Specifically, the operation data generator 630 may select the first panel block having the greatest load data LD among the panel blocks based on the load data LD. The operation data generator 630 may select the second panel block having the greatest life data AD among the panel blocks based on the life data AD. The operation data generator 630 generates the start time gain data for adjusting the start time TSS of the screen saver mode based on the load data LD of the first panel block and the life data AD of the second panel block. In addition, the operation data generator 630 may generate the minimum luminance gain data for adjusting the minimum luminance LM of the screen saver mode based on the load data LD of the first panel block and the life data AD of the second panel block. For example, the start time TSS of the screen saver mode of the display device 10 may be earlier in proportion to the load data LD of the first panel block and the life data AD of the second panel block. In another example, the minimum luminance LM of the screen saver mode of the display device 10 is lowered in proportion to the load data LD of the first panel block and the life data AD of the second panel block.

[0031] In an embodiment, the operation data generator 630 generates the start time gain data and the minimum luminance gain data based on an average of the load data LD of the panel blocks, and an average of the life data AD of the panel blocks. Specifically, the operation data generator 630 may calculate the average of the load data LD of the panel blocks based on the load data LD. The operation data generator 630 may calculate the average of the life data AD of the panel blocks based on the life data AD. The operation data generator 630 may generate the start time gain data for adjusting the start time TSS of the screen saver mode based on the average of the load data LD of the panel blocks and the average of the life data AD of the panel blocks. In addition, the operation data generator 630 may generate the minimum luminance gain data for adjusting the minimum luminance LM of the screen saver mode based on the average of the load data LD of the panel blocks and the average of the life data AD of the panel blocks. For example, the start time TSS of the screen saver mode of the display device 10 may be earlier in proportion to the average of the load data LD of the panel blocks and the average of the life data AD of the panel blocks. In another example, the minimum luminance LM of the screen saver mode of the display device 10 is lowered in proportion to the average of the load data LD of the panel blocks and the average of the life data AD of the panel blocks.

[0032] The screen saver data generator 640 generates the screen saver data SSD based on the input image data IMG The screen saver data generator 640 may receive the input image data IMG from the timing controller 200. The screen saver data generator 640 may receive the gain data GD from the operation data generator 630. In an embodiment, the screen saver data generator 640 generates the screen saver data SSD based on input image data IMG and the gain data GD, and transmits the screen saver data SSD to the timing controller 200. The timing controller 200 may allow the display panel 100 to operate in the screen saver mode to adjust the luminance of the display panel 100.

[0033] Accordingly, the screen saver controller of the present inventive concept provides the screen saver mode optimized for the display panel 100 by using the load data LD and the life data AD of the display panel 100, so that visual recognition of an afterimage on the display panel 100 can be improved and the lifespan of the display panel 100 can be increased.

[0034] FIG 6 is a graph illustrating a change in luminance of an image displayed on the display panel 100 when the screen saver mode is operated. The screen saver data SSD is display data for operating the screen saver mode, and results in the graph illustrated in FIG 6. In this way, the screen saver data SSD may comprise luminance and timing data for displaying an image on the display panel 100 according to the graph shown in FIG 6. FIG 7 is a diagram illustrating an example of a change in luminance of an image displayed on the display panel 100 for each period of FIG 6. FIG 8 is a graph illustrating a change in pixel life according to a driving time of the display device 10 when the screen saver data generator 640 generates the screen saver data SSD based on the gain data GD.

[0035] Referring to FIGS. 3 to 8, the display device 10 determines whether to operate in the screen saver mode based on the input image data IMG The display device 10 determines whether the image displayed on the display panel 100 is a still image based on the input image data IMG When the still image displayed on the display panel 100 continues for a predetermined period of time, the screen saver controller 600 may generate the screen saver data SSD based on the input image data IMG and output the screen saver data SSD to the timing controller 200.

[0036] In an embodiment, the screen saver controller 600 provides the screen saver mode optimized for the display panel 100 based on the load data LD and the life data AD. Specifically, the screen saver controller 600 may optimize the start time TSS of the screen saver mode based on the load data LD and the life data AD. For example, the operation data generator 630 generates the start time gain data based on the load data LD and the life data AD. Referring to FIG 6, as the load data LD and life data AD increases, the start time TSS of the screen saver mode may be decreased or moved to an earlier time. In other words, when the load data LD and life data AD become large, the screen saver mode start time TSS may be shifted leftward in a time axis (X-axis) of the graph of FIG 6. In an embodiment, life data AD is large when it is determined that an after image is likely to be perceived in one or more of the panel blocks in the near future, and the life data AD is not large when it is determined that an after image is not likely to be perceived in the near future. In addition, the screen saver controller 600 may optimize the minimum luminance LM of the screen saver mode based on the load data LD and the life data AD. For example, the operation data generator 630 may generate the minimum luminance gain data based on the load data LD and the life data AD. Referring to FIG 6, as the load data LD and life data AD increases, the minimum luminance LM of the screen saver mode may be decreased. In other words, when the load data LD and life data AD become large, the minimum luminance LM of the screen saver mode may shifted downward in a luminance axis (Y-axis) of the graph of FIG 6.

[0037] In an embodiment, when the display device 10 operates in the screen saver mode, the luminance of the display panel 100 is gradually decreased as in a second period P2. Referring to FIG 7, the display panel 100 maintains the minimum luminance as in a third period P3 from the point (TSM) when the luminance of the display panel 100 is decreased to the minimum luminance of the screen saver mode. Meanwhile, during a screen saver mode operation, the screen saver mode may be canceled or be exited at the time when a predetermined change occurs (TSE) as in a fourth period P4, and the luminance of the display panel 100 may be increased to a normal luminance LI. For example, the luminance of the display panel 100 in a first period P1 may be the normal luminance LI in which the screen saver mode is not operated. The display panel 100 in the second period P2 may have a luminance between the normal luminance LI and the minimum luminance LM. The display panel 100 in the third period P3 may have the minimum luminance LM of the screen saver mode. For example, during the fourth period P4, the image data IMG may correspond to a moving image.

[0038] Referring to FIG 8, when the screen saver data generator 640 generates the screen saver data SSD based on the input image data IMG and the gain data GD, the luminance of the display panel 100 in the third period P3 is lower than when the screen saver data generator 640 generates the screen saver data SSD based only on the input image data IMG Accordingly, the lifespan of the pixels included in the display panel 100 may be increased when the screen saver data generator 640 generates the screen saver data SSD based on the gain data GD compared to the case where the screen saver data SSD is generated without the gain data GD. In particular, a difference in pixel life may be increased when the driving time of the display panel 100 is increased. In other words, when the screen saver data generator 640 generates the screen saver data SSD based on the gain data GD, the display panel 100 may receive less deterioration stress.

[0039] Accordingly, when the display device 10 of the present inventive concept operates in the screen saver mode optimized for the display panel 100 by using the load data LD generated by the load calculator 610 and the life data AD generated by the life calculator 620, visual recognition of an afterimage on the display panel 100 can be improved and lifespan of the display panel 100 can be increased.

[0040] FIG 9 is a flowchart illustrating an example in which the screen saver mode is executed in the display device 10.

[0041] Referring to FIG 9, the display device 10 of the present inventive concept generates the load data LD of the panel blocks based on the input image data IMG (S 100), generates life data AD of each of the panel blocks based on the deterioration stress values accumulated in the display panel 100 (S200), generates the gain data GD based on the load data LD and the life data AD (S300), generates the screen saver data SSD based on the input image data IMG and the gain data GD (S400), and determines whether to operate in the screen saver mode based on the input image data IMG (S500). In an embodiment, the display device 10 determines whether to operate in the screen saver mode when the input image data IMG includes a static or non-moving image and / or when an average intensity of one of the panel blocks exceeds a certain threshold. When the display device 10 operates in the screen saver mode, the display device 10 adjusts the luminance of the display panel 100 based on the screen saver data SSD (S600), and outputs an image to the display panel 100 (S700). Meanwhile, when the display device 10 does not operate in the screen saver mode, the display device 10 outputs the image to the display panel 100 without adjusting the luminance of the display panel 100 (S700).

[0042] In one embodiment, the load calculator 610 and the life calculator 620 calculate load data LD and life data AD that serve as criteria of the gain data GD. The load calculator 610 may generate the load data LD of the panel blocks based on the input image data IMG (S100). Specifically, the load calculator 610 may store load data LD corresponding to the input image data IMG in the form of a lookup table LUT. The load calculator 610 may select the load data LD corresponding to the input image data IMG from the lookup table, calculate the load data LD of each of the panel blocks and transmit the load data LD to the operation data generator 630. The life calculator 620 generates life data AD of each of the panel blocks based on deterioration stress values accumulated in the display panel 100 (S200). Specifically, the life calculator 620 accumulates deterioration stress values of the display panel 100 to generate an accumulated stress value and may store the accumulated deterioration stress value into a nonvolatile memory device, and generate the life data AD according to the accumulated deterioration stress value. In an embodiment, an increase in the life data AD signifies that the deterioration stress applied to the panel block is large or greater than a threshold.

[0043] In an embodiment, the operation data generator 630 generates the gain data GD based on the load data LD and the life data AD (S300). For example, the operation data generator 630 may generate start time gain data for adjusting the start time TSS of the screen saver mode according to the load data LD and the life data AD. The operation data generator 630 generates the start time gain data for allowing the screen saver mode to be adjusted to start earlier as the load data LD increases. The operation data generator 630 may generate the start time gain data for allowing the screen saver mode to be adjusted to start earlier as the life data AD increases. In another example, the operation data generator 630 may generate minimum luminance gain data for adjusting the minimum luminance LM of the screen saver mode according to the load data LD and the life data AD. The operation data generator 630 may generate the minimum luminance gain data for adjusting the minimum luminance of the screen saver mode to be lower as the load data LD increases. The operation data generator 630 may generate the minimum luminance gain data for adjusting the minimum luminance of the screen saver mode to be lower as the life data AD increases.

[0044] In an embodiment, the screen saver data generator 640 generates the screen saver data SSD based on the input image data IMG and the gain data GD (S400). The screen saver data generator 640 may receive the input image data IMG from the timing controller 200. The screen saver data generator 640 may receive the gain data GD from the operation data generator 630. The screen saver data generator 640 may generate the screen saver data SSD based on input image data IMG and the gain data GD, and transmit the screen saver data SSD to the timing controller 200.

[0045] Accordingly, the screen saver controller of the present inventive concept provides the screen saver mode optimized for the display panel 100 by using the load data LD and the life data AD of the display panel 100.

[0046] The screen saver controller determines whether to operate the screen saver mode based on the input image data IMG (S500). When the display device 10 operates in the screen saver mode, the display device 10 may adjust the luminance of the display panel 100 based on the screen saver data SSD (S600), and output an image to the display panel 100 (S700). Specifically, when the display device 10 operates in the screen saver mode, the luminance of the display panel 100 is gradually decreased. When the luminance of the display panel 100 is decreased to the minimum luminance of the screen saver mode, the display panel 100 maintains the minimum luminance. Meanwhile, during a screen saver mode operation, when a predetermined change occurs, the screen saver mode may be canceled or exited and the luminance of the display panel 100 may be increased to a normal luminance LI. In an embodiment, when the display device 10 does not operate in the screen saver mode, the display device 10 outputs the image to the display panel 100 without adjusting the luminance of the display panel 100 (S700). For example, the predetermined condition could be the image data IMG indicating a moving image.

[0047] The lifespan of the pixels included in the display panel 100 according to an embodiment of the present inventive concept may be increased when the screen saver data generator 640 generates the screen saver data SSD based on the gain data GD compared to the case where the screen saver data SSD is generated without the gain data GD. In particular, a difference in pixel life may be increased when the driving time of the display panel 100 is increased. In other words, when the screen saver data generator 640 generates the screen saver data SSD based on the gain data GD, the display panel 100 may receive less deterioration stress. Accordingly, the screen saver controller of the present inventive concept may provide the screen saver mode optimized for the display panel 100 by using the load data LD and the life data AD of the display panel 100, so that visual recognition of an afterimage on the display panel 100 can be improved and lifespan of the display panel 100 can be increased.

[0048] FIG 10 is a block diagram illustrating an electronic device according to an embodiments of the present inventive concept. FIG 11 is a diagram illustrating an example in which the electronic device of FIG 10 is implemented as a smartphone.

[0049] Referring to FIGS. 10 and 11, the electronic device 1000 includes a processor 1010, a memory device 1020, a storage device 1030, an input / output (I / O) device 1040, a power supply 1050, and a display device 1060. In addition, the electronic device 1000 may further include a plurality of ports for communicating with a video card, a sound card, a memory card, a universal serial bus (USB) device, or another electronic device. In an embodiment, as illustrated in FIG 11, the electronic device 1000 may be implemented as a smart phone. However, the electronic device 1000 is not limited thereto. For example, the electronic device 1000 may be implemented as a cellular phone, a video phone, a smart pad, a smart watch, a tablet PC, a car navigation system, a computer monitor, a laptop, or a head mounted display (HMD) device.

[0050] The processor 1010 may perform various computing functions. The processor 1010 may be a micro-processor, a central processing unit (CPU), or an application processor (AP). The processor 1010 may be coupled to other components via an address bus, a control bus, or a data bus. Further, the processor 1010 may be coupled to an extended bus such as a peripheral component interconnection (PCI) bus. The memory device 1020 may store data for operations of the electronic device 1000. For example, the memory device 1020 may include at least one non-volatile memory device such as an erasable programmable read-only memory (EPROM) device, an electrically erasable programmable read-only memory (EEPROM) device, a flash memory device, a phase change random access memory (PRAM) device, a resistance random access memory (RRAM) device, a nano floating gate memory (NFGM) device, a polymer random access memory (PoRAM) device, a magnetic random access memory (MRAM) device, and a ferroelectric random access memory (FRAM) device, and / or at least one volatile memory device such as a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, or a mobile DRAM device. The storage device 1030 may include a solid state drive (SSD) device, a hard disk drive (HDD) device, or a CD-ROM device. The I / O device 1040 may include an input device such as a keyboard, a keypad, a mouse device, a touch-pad, or a touch-screen, and an output device such as a printer or a speaker. In some embodiments, the I / O device 1040 may include the display device 1060. The power supply 1050 may provide power for operations of the electronic device 1000.

[0051] The display device 1060 may display an image corresponding to visual information of the electronic device 1000. The display device 1060 may include a display panel including a plurality of pixels, a data driver for providing a data signal to the display panel, a gate driver for providing a gate signal to the display panel, a timing controller for controlling the data driver and the gate driver and a screen saver controller for determining whether to operate a first mode based on input image data, and adjusting a luminance of the display panel based on screen saver data during operating the first mode. For example, the display device 1060 may include the display panel driver 120. The screen saver controller may include a load calculator for generating load data of each of a plurality of panel blocks included in a display panel based on input image data, a life calculator for generating life data of each of the panel blocks based on deterioration stress value accumulated in the display panel, an operation data generator for receiving the load data and the life data, and generating operation data based on the load data and the life data and a screen saver data generator for receiving the input image data and the operation data, and generating screen saver data based on the input image data and the operation data. The screen saver controller may determine whether to operate in a first mode based on the input image data, and adjust a luminance of the display panel based on the screen saver data during operating the first mode. The screen saver controller may provide a screen saver mode optimized for the display panel by using the load data and the life data of the display panel, so that visual recognition of an afterimage of the display panel can be improved. In addition, the screen saver controller may provide a screen saver mode optimized for the display panel by using the load data and the life data of the display panel, so that the lifespan of the display panel can be increased.

[0052] The foregoing is illustrative of the present inventive concept and is not to be construed as limiting thereof. Although a few embodiments of the present inventive concept have been described, those of ordinary skill in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the present inventive concept, insofar as such modified embodiments are included within the scope of the present claims.

Claims

1. A display device (10) including a display panel with a plurality of panel blocks, and further including a screen saver controller (600), the controller comprising: a load calculator (610) configured to generate load data (LD) of each of the plurality of panel blocks (110, 120) included in the display panel (100) based on input image data (IMG), wherein the load data of a given panel block is calculated from an average intensity of intensities of the pixels (P) in the given panel block, or the load data is generated from an average voltage of data voltages applied to the pixels of the given panel block; a life calculator (620) configured to generate life data (AD) of each of the panel blocks, wherein the life data of a given panel block is a sum of deterioration stress values accumulated in the given panel block, wherein the life data of the given panel block increases as an accumulated usage amount of the given panel block increases; a first logic circuit (630) configured to receive the load data and the life data, and to generate gain data (GD) based on the load data and the life data; and a second logic circuit (640) configured to receive the input image data and the gain data, and to generate screen saver data (SSD) based on the input image data and the gain data, wherein the display device is configured to operate in a screen saver mode in response to determining, based on the input image data, that an image displayed on the display panel is a still image, and the screen saver controller is configured to adjust a luminance of the display panel based on the screen saver data in response to the display device operating in the screen saver mode for performing a screen saver operation, such to maintain for a first period (P1) a luminance of the display panel until a start time (TSS) of the screen saver operation, and to perform the screen saver operation starting at the start time (TSS), wherein the screen saver operation includes gradually decreasing, for a second period (P2), the luminance of the display panel until it reaches a set minimum luminance, and maintaining the minimum luminance for a third period (P3); wherein the gain data includes start time gain data for adjusting the start time (TSS) of the screen saver operation based on the load data and the life data, wherein the first logic circuit is configured to generate the start time gain data such to control the start time (TSS) of the screen saver operation to start earlier as an average value of the load data of the panel blocks increases and wherein the first logic circuit is configured to generate the start time gain data such to control the start time (TSS) of the screen saver operation to start earlier as an average value of the life data of the panel blocks increases.

2. The display device of claim 1, wherein the gain data includes minimum luminance gain data for adjusting the minimum luminance of the screen saver operation based on the load data and the life data, wherein the first logic circuit is configured to generate the minimum luminance gain data for adjusting the minimum luminance of the screen saver mode to be lower as the average value of the load data increases and wherein the first logic circuit is configured to generate the minimum luminance gain data for adjusting the minimum luminance of the screen saver mode to be lower as the average value of the life data increases.

3. The display device of any preceding claim, wherein the load calculator is configured to generate the load data according to a lookup table in which the load data corresponding to the input image data is stored.

4. A method of operating the display device (100) of claim 1, the method comprising: by the display device, operating in the screen saver mode in response to determining, based on the input image data, that an image displayed on the display panel is a still image; by the screen saver controller: generating the load data (LD) of each of the plurality of panel blocks (110, 120) included in the display panel of the display device; generating the life data (AD) of each of the panel blocks; generating the gain data ; and generating the screen saver data (SSD) such to maintain for the first period (P1) the luminance of the display panel until the start time (TSS) of the screen saver operation, and to perform the screen saver operation starting at the start time (TSS), wherein the screen saver operation includes gradually decreasing, for the second period (P2), the luminance of the display panel until it reaches a set minimum luminance, and maintaining the minimum luminance for the third period (P3); and wherein the generating of the gain data includes: generating the start time gain data (GD) for adjusting the start time of the screen saver operation based on the load data and the life data, the start time gain data being such to control the start time of the screen saver operation to start earlier as the average value of the load data increases and the start time gain data being such to control the screen saver mode to start earlier as the average value of the life data increases.

5. The method of claim 4, wherein the generating the gain data further includes: generating minimum luminance gain data for adjusting the minimum luminance of the screen saver mode based on the load data and the life data, the minimum luminance gain data being for adjusting the minimum luminance of the screen saver mode to be lower as the average value of the load data increases and the minimum luminance gain data being for adjusting the minimum luminance of the screen saver mode to be lower as the average value of the life data increases.