Signal processing device, signal processing method, and display device

Abstract

This technology relates to a signal processing device, signal processing method, and display device that can more appropriately improve blur retention. The device includes a detection unit that analyzes a video signal of a content and detects an indicator related to blur retention; a first calculation unit that calculates a light duty cycle of a self-luminous display panel based on the detected indicator; and a second calculation unit that calculates a gain for brightness compensation based on the calculated light duty cycle. This technology can be applied, for example, to self-luminous display devices.

Description

Technical Field

[0001] The present technology relates to a signal processing device, a signal processing method, and a display device, and more particularly, to a signal processing device, a signal processing method, and a display device capable of more appropriately improving retention blur. Background Art

[0002] In recent years, OLED displays, which are becoming mainstream as video display devices, are hold-type displays. It is reported that such displays may exhibit hold blur due to human visual characteristics.

[0003] Various proposals have been made as methods for improving this lingering blur. For example, a liquid crystal display device has been proposed that improves lingering blur by controlling the driving of a backlight provided on a liquid crystal display panel according to the motion of an object included in video content (see Patent Document 1).

[0004] Reference List

[0005] Patent Literature

[0006] Patent document 1: International Publication No. 2019 / 124254. Summary of the Invention

[0007] Problems to be solved by the present invention

[0008] Incidentally, even self-luminous display devices such as OLED display devices need to be improved in maintaining blur, but a technical method for this has not yet been established.

[0009] The present technology has been made in view of such circumstances and can improve the preservation blur more appropriately.

[0010] Solution to the problem

[0011] A signal processing device according to one aspect of the present technology is a signal processing device, comprising: a detection unit configured to analyze a video signal of content and detect an indicator related to maintaining blur; a first calculation unit configured to calculate a luminous duty value of a self-luminous display panel based on the detected indicator; and a second calculation unit configured to calculate a gain for brightness compensation based on the calculated luminous duty value.

[0012] A signal processing method according to one aspect of the present technology is a signal processing method comprising the following steps: analyzing a video signal of content by a signal processing device and detecting an indicator related to maintaining blur; calculating a luminous duty value of a self-luminous display panel based on the detected indicator; and calculating a gain for brightness compensation based on the calculated luminous duty value.

[0013] A display device according to one aspect of the present technology is a display device including the following components: a signal processing unit configured to process a video signal of content; a self-luminous display panel configured to display a video of the content; and a display panel driving unit configured to drive the self-luminous display panel based on the video signal from the signal processing unit, wherein the signal processing unit includes: a detection unit configured to analyze the video signal of the content and detect an indicator related to maintaining blur; a first calculation unit configured to calculate a luminous duty value of the self-luminous display panel based on the detected indicator; and a second calculation unit configured to calculate a gain for brightness compensation based on the calculated luminous duty value; and the display panel driving unit drives the self-luminous display panel based on the luminous duty value and gain calculated by the signal processing unit.

[0014] In a signal processing device, a signal processing method, and a display device according to one aspect of the present technology, a video signal of content is analyzed and an indicator related to maintaining blur is detected, a luminous duty value of a self-luminous display panel is calculated based on the detected indicator, and a gain for brightness compensation is calculated based on the calculated luminous duty value.

[0015] It should be noted that the signal processing device or the display device according to an aspect of the present technology may be an independent device or may be an internal block constituting one device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a block diagram illustrating an example of the configuration of an embodiment of a signal processing device to which the technology of the present invention is applied.

[0017] Figure 2 It shows Figure 1 A block diagram of an example of a detailed configuration of a signal processing device.

[0018] Figure 3 1 is a diagram illustrating an example of improving the retention blur by black insertion driving.

[0019] Figure 4 is a graph showing an example of luminance compensation during black insertion driving.

[0020] Figure 5 is a table showing an example of the relationship between the light emission duty ratio, gain, moving image display performance, and self-luminous element stress.

[0021] Figure 6 is a graph showing an example of controlling the light emission duty ratio according to the amount of motion.

[0022] Figure 7 is a graph showing an example of controlling the light emission duty ratio according to the detail level.

[0023] Figure 8is a graph showing an example of comparison of driving currents in OLED elements when displaying colors.

[0024] Figure 9 is a graph showing an example of peak brightness control.

[0025] Figure 10 is a graph showing an example of controlling the light emission duty ratio according to the saturation level.

[0026] Figure 11 Graph showing an example of gamma correction during black insertion driving.

[0027] Figure 12 : is a graph showing an example of an effective light emitting period during normal driving and black insertion driving.

[0028] Figure 13 is a graph showing an example of controlling the light emission duty ratio according to the average pixel level.

[0029] Figure 14 is a diagram illustrating an example of current fluctuation of a power supply circuit for driving an OLED element.

[0030] Figure 15 is a graph showing an example of peak current control.

[0031] Figure 16 is a block diagram illustrating an example of the configuration of an embodiment of a self-luminous display device to which the technology of the present invention is applied. DETAILED DESCRIPTION

[0032] <1. Embodiments of the present technology>

[0033] (Configuration of Signal Processing Device)

[0034] Figure 1 is a diagram illustrating an example of the configuration of an embodiment of a signal processing device to which the technology of the present invention is applied.

[0035] Figure 1 The present invention shows a signal processing device 10 that processes an input signal from a signal input unit (not shown) provided in a front stage, and a panel driver 20 that drives an OLED display panel (not shown) provided in a rear stage. The signal processing device 10 and the panel driver 20 are connected via a plurality of signal lines 30 and a control line 40.

[0036] The signal processing device 10 outputs a video signal to the panel driver 20 via a signal line 30. In addition, the signal processing device 10 outputs a control signal to the panel driver 20 via a control line 40.

[0037] The signal processing device 10 performs predetermined signal processing based on the input signal input thereto. In this signal processing, a video signal for controlling the driving of the OLED display panel is generated and provided to the panel driver 20.

[0038] The panel driver 20 drives the OLED display panel in the subsequent stage based on the video signal supplied from the signal processing device 10 .

[0039] The OLED display panel is a display panel in which pixels including OLED elements are arranged in a two-dimensional shape (matrix shape), and displays video according to the drive from the panel driver 20. The OLED display panel is an example of a self-luminous display panel using OLED elements as self-luminous elements. Figure 16 Details of a self-luminous display device having a self-luminous display panel are described.

[0040] Organic light-emitting diodes (OLEDs) are light-emitting elements with an organic light-emitting material sandwiched between a cathode and an anode. They form pixels (display pixels) arranged two-dimensionally on an OLED display panel. The OLED elements included in the pixels are driven according to a drive control signal generated by signal processing. In an OLED display panel, each pixel (display pixel) includes four sub-pixels, for example, red (R), green (G), blue (B), and white (W).

[0041] Figure 2 Show Figure 1 Detailed configuration of the signal processing device 10.

[0042] exist Figure 2 In the figure, the signal processing device 10 includes an image flatness detection unit 101, a saturation detection unit 102, a motion detection unit 103, an APL detection unit 104, an optimal duty value calculation unit 105, a gain calculation unit 106, a peak current control unit 107 and an offset calculation unit 108.

[0043] The image flatness detection unit 101 performs image flatness detection processing on the video signal input thereto, and supplies the detail level (Detail_Lev) obtained as a result of the processing to the optimal duty value calculation unit 105 .

[0044] For example, image frames containing fine details (including many edges) tend to be blurry, but not flat parts. Therefore, in the image flatness detection process, the spatial resolution of the multiple image frames that make up the video is analyzed to detect the detail level as an indicator of the edge portions included in the video signal. As a method for detecting the detail level, for example, a bandpass filter that only passes specific frequencies can be used for detection.

[0045] The saturation detection unit 102 performs saturation detection processing on the video signal input thereto, and supplies a saturation level (Color_Sat_Lev) obtained as a result of the processing to the optimum duty value calculation unit 105 .

[0046] For example, in the saturation detection process, the saturation level is detected as an index representing characteristics related to the vividness of the video by analyzing a color signal or the like obtained from the video signal.

[0047] The motion detection unit 103 performs motion detection processing on the video signal input thereto, and supplies the amount of motion (Motion) obtained as a result of the processing to the optimal duty value calculation unit 105 .

[0048] For example, unless the object displayed as a video (display object) is moving, no hold blur occurs. Therefore, in the motion detection process, the amount of motion is detected as an indicator of the motion of the object displayed in the video. As a method for detecting the amount of motion, for example, the brightness difference of each pixel between image frames or the motion vector of the display object can be used for detection.

[0049] The APL detection unit 104 performs APL detection processing on the video signal input thereto, and supplies the average pixel level (Ave_Pix_Lev) obtained as a result of the processing to the optimal duty value calculation unit 105 .

[0050] For example, in the APL detection process, by obtaining the average value of pixel levels of image frames constituting a video, the average pixel level is detected as an index representing characteristics related to the video.

[0051] In this manner, the image flatness detection unit 101, the saturation detection unit 102, the motion detection unit 103, and the APL detection unit 104 constitute the detection unit 100, which analyzes the video signal of the content and detects various parameters as indicators related to preserving blur. Then, at least one of the four parameters (Detail_Lev, Color_Sat_Lev, Motion, and Ave_Pix_Lev) detected by the detection unit 100 is provided to the optimal duty value calculation unit 105.

[0052] It should be noted that the video signal processed by the detection unit 100 is output to the panel driver 20 via the signal line 30 .

[0053] The optimal duty value calculation unit 105 calculates the optimal light emission duty value (Duty) based on the parameters provided from the detection unit 100, and provides the optimal duty value to the panel driver 20 ( Figure 1), the gain calculation unit 106 or the offset calculation unit 108. The light emission duty value is a light emission duty ratio of the OLED elements arranged on the OLED display panel, and is also referred to as light emission duty hereinafter.

[0054] The gain calculation unit 106 calculates a gain for brightness compensation based on the light emission duty value supplied from the optimal duty value calculation unit 105 , and supplies the gain to the panel driver 20 or the peak current control unit 107 .

[0055] The peak current control unit 107 calculates a current limit value (Cur_ratio) based on the gain supplied from the gain calculation unit 106 and supplies the current limit value (Cur_ratio) to the panel driver 20 .

[0056] The offset calculation unit 108 calculates an offset value (Offset) related to the brightness of the video signal based on the light emission duty value supplied from the optimal duty value calculation unit 105 , and supplies the offset value to the panel driver 20 .

[0057] A control signal including at least one of the following four parameters: a light emission duty value (Duty), a gain (Gain), a current limit value (Cur_ratio), and an offset value (Offset) is input from the signal processing device 10 to the panel driver 20 via a control line 40. The panel driver 20 drives the OLED display panel in the subsequent stage based on the parameters included in the control signal.

[0058] The signal processing device 10 is configured as described above.

[0059] (Example of black driver insertion)

[0060] Incidentally, self-luminous display devices such as OLED displays are hold-type display devices similar to non-self-luminous display devices such as liquid crystal displays. In a hold-type display device, in principle, pixels arranged two-dimensionally on a display unit display the same brightness during one frame (hold-type display). Therefore, hold blur is known to occur in this type of display device due to the characteristics of human vision.

[0061] For example, in an OLED display device, when the user's eyes follow a moving display object within a frame while the light is continuously illuminated during a frame period, the user perceives the display object as a persistent afterimage. Reducing the OLED element's light emission duty cycle improves the persistence blur, but to maintain brightness, the gain needs to be increased by the inverse of the light emission duty cycle (1 / duty).

[0062] Figure 3 An example of improving the retention blur by black insertion driving is shown. Figure 3 A and B show the actual movement and visual effect during normal driving, while Figure 3 Figures C and D show the actual movement and visual effects during black insertion driving.

[0063] In normal driving, driving is performed with a 100% emission duty (Duty 100%). On the other hand, in black insertion driving, the video display time is shortened by providing a black display period during the display period used to display the same video (image frame). This black insertion driving can improve the performance of moving image display. In black insertion driving, the emission duty can be varied within the range of Duty 50% to Duty 100%. In this example, the case of driving with a 50% emission duty (Duty 50%) will be described.

[0064] exist Figure 3 , the time direction is from left to right, and image frames F1, F2, and F3 are displayed in sequence during 0, 1 / 240 seconds, 2 / 240 seconds, 3 / 240 seconds, and 4 / 240 seconds.

[0065] In execution Figure 3 In the case of actual movement of normal driving shown in A, when the eyes follow the moving display object (ball) in image frame F, the user feels a retention type afterimage, as shown in FIG. Figure 3 The normal driving visual effect is shown in B.

[0066] On the other hand, in the implementation Figure 3 In the case of black insertion drive described in C, the blur can be improved, such as Figure 3 The black insertion driving visual effect is shown in FIG. However, when the light-emitting duty cycle is reduced, the brightness is reduced accordingly.

[0067] Figure 4 An example of brightness compensation during black insertion driving is shown. Figure 4 , the horizontal axis represents time, and the vertical axis represents brightness level.

[0068] exist Figure 4 In FIG, waveform L11 shows the light emission waveform of the OLED element during normal driving. The light emission waveform of normal driving represents a constant fixed brightness level, 100% light emission duty (Duty 100%), and 1-time gain (Gain×1).

[0069] Waveform L12 shows the light emission waveform of the OLED element during black insertion driving. The light emission waveform of the black insertion driving is a rectangular wave, and represents a 50% light emission duty (Duty 50%) and a double gain (Gain×2).

[0070] In this way, when the duty becomes Duty 50% during black insertion driving, brightness compensation is performed by increasing the gain to double the brightness when the OLED element emits light so that the average brightness becomes the same as that of Duty 100%.

[0071] (Based on motion and edge control)

[0072] Figure 5 is an example showing the relationship between the light emission duty ratio, gain, moving image display performance, and self-luminous element stress.

[0073] like Figure 5 As shown in [1], while doubling the gain improves display performance for moving images by reducing the emission duty cycle to 50% to maintain constant brightness, the stress on self-luminous elements such as OLEDs increases. Therefore, for still images, it is necessary to restore the emission duty cycle to 100% to reduce stress on the OLEDs and prevent degradation of their lifespan.

[0074] For example, in a liquid crystal display device, in order to improve hold-type hold blur, a method of reducing the duty cycle for lighting a backlight such as a light emitting diode (LED) and increasing the gain for brightness compensation is used in an image frame including a fast-moving display object.

[0075] On the other hand, in still image frames, the duty cycle is set to 100%, and the gain is restored to minimize temperature rise and stress on the LEDs, achieving both reliability and performance for moving images. Furthermore, in fine video (clear image frames with high-frequency components), the duty cycle is reduced to enhance the effect of improving blur retention.

[0076] Since the OLED display device has an OLED element which is a self-luminous element, it is possible to improve the retention blur by changing the configuration of a drive circuit within the display unit and performing black insertion driving to control the light emission duty, as has been described above.

[0077] In OLED display devices, gain can be applied to compensate for brightness reduction during black insertion driving to suppress brightness reduction. However, if this driving is always performed, stress on the OLED elements increases and their lifespan is shortened. Therefore, in this technology, the light emission duty cycle is controlled based on parameters such as the amount of motion indicating the motion of the displayed object and the level of detail indicating the fineness of the video.

[0078] Specifically, in the signal processing device 10 , the optimum duty value calculation unit 105 calculates the optimum light emission duty value using the amount of motion detected by the motion detection unit 103 , so that the retaining blur of the moving image can be improved.

[0079] Figure 6 An example of controlling the light emission duty according to the amount of motion is shown. Figure 6 In the figure, the horizontal axis represents the amount of motion (Motion), and the vertical axis represents the luminous duty value.

[0080] Figure 6 The figure shows that the amount of motion of the object displayed in the video increases as the value on the horizontal axis moves to the right, and the luminous duty cycle value increases as the value on the vertical axis moves upward. Since blurring is easily seen in videos containing displayed objects with large amounts of motion, control is performed to reduce the luminous duty cycle, as indicated by polygonal line L21. On the other hand, in videos with small amounts of motion, such as still images, control is performed to increase the luminous duty cycle, as indicated by polygonal line L21. In other words, as the detected amount of motion increases, the luminous duty cycle value decreases.

[0081] In addition, in the signal processing device 10, the optimal duty value calculation unit 105 calculates the optimal light emission duty value using the detail level detected by the image flatness detection unit 101, so that the preservation blur of a clear video with high-frequency components (including an image frame of an edge) can be improved.

[0082] Figure 7 An example of controlling the light emission duty according to the detail level is shown. Figure 7 , the horizontal axis represents the detail level (Detail_Lev), and the vertical axis represents the luminous duty value.

[0083] Figure 7 As the horizontal axis moves to the right, the video becomes more detailed and includes more edge portions, while the luminous duty value increases as the vertical axis moves upward. Because blurring is easily visible in detailed images, control is performed to reduce the luminous duty, as indicated by polygonal line L22. On the other hand, in flat video, control is performed to increase the luminous duty, as indicated by polygonal line L22. In other words, the luminous duty value decreases as the detected level of detail increases.

[0084] By controlling the light emission duty in this way, the blurring can be improved. In addition, the stress on the OLED element can be reduced, and the reduction in the life of the OLED element can be suppressed.

[0085] (According to saturation control)

[0086] In an OLED display device, multiple pixels are arranged two-dimensionally in the display area of the OLED display panel. Each pixel includes four sub-pixels: a sub-pixel R that generates red (R) light, a sub-pixel G that generates green (G) light, a sub-pixel B that generates blue (B) light, and a sub-pixel W that generates white (W) light. In other words, the two-dimensionally arrayed pixels in the display area of the OLED display panel are RGBW pixels.

[0087] Here, each pixel in the display area of the OLED display panel is configured as an RGBW pixel. When the pixel is lit at 100% level, subpixels R, G, and B have lower luminous efficiency and greater current than subpixel W. This is because color filters corresponding to the wavelength bands of the respective colors pass through them. Therefore, the upper limit of the gain of subpixels R, G, and B is lower than the upper limit of the gain of subpixel W.

[0088] Furthermore, since complementary colors such as yellow (Y), magenta (M), and cyan (C) light up two sub-pixels in each pixel, if the pixel is lit at the maximum level as it is, the current limit value will be exceeded.

[0089] Therefore, the brightness level of the entire display area of the OLED display panel needs to be reduced to maintain the brightness level within the current limit value. This current limit value depends on the temperature increase of the panel due to self-heating of the OLED element and the current capacity limitation of the power supply.

[0090] It should be noted that in each pixel, when sub-pixel R and sub-pixel G are lit, the color changes to yellow (Y), when sub-pixel R and sub-pixel B are lit, the color changes to magenta (M), and when sub-pixel G and sub-pixel B are lit, the color changes to cyan (C).

[0091] Figure 8 An example of comparison of driving currents in OLED elements when displaying respective colors is shown. Figure 8 In the figure, the horizontal axis represents the sub-pixel colors (W, R, G, and B) and the colors when two sub-pixels are lit (Y, M, and C), while the vertical axis represents the EVDD current value. The EVDD current represents the total current flowing through the OLED element in the entire display area of the OLED display panel.

[0092] like Figure 8 As shown in the figure, since sub-pixels R, G, and B have higher EVDD current values than sub-pixel W, the upper limit of the gain is lower. In addition, when the pixels are lit at the maximum level, complementary colors such as yellow (Y), magenta (M), and cyan (C) exceed the current limit value shown by the dotted line in the figure. Therefore, as shown by the bold lines D1 to D3 in the figure, the brightness level of the entire display area of the OLED display panel is reduced to keep the current value within the current limit value.

[0093] Here, the brightness of the sub-pixel W during the black insertion driving period for performing brightness compensation can match the brightness during the driving period without black insertion. It should be noted that at this time, the brightness level is the brightness of the input level of 100%, and for convenience, the brightness levels of the sub-pixels R, G, and B during the driving period without black insertion are the same as the brightness of the sub-pixel W.

[0094] For example, in the case of Duty 50% during black insertion driving, the brightness of sub-pixel W can be compensated by doubling the gain, while sub-pixels R, G and B have an upper limit value of the gain, and the brightness level is reduced by reducing the light-emitting duty in areas with low average pixel levels (APL) in the display area.

[0095] Figure 9 An example of peak brightness control during black insertion driving for performing brightness compensation is shown. Figure 9 , the horizontal axis represents the average pixel level (APL), and the vertical axis represents the brightness level.

[0096] exist Figure 9 , the polygonal line L31 represents the control of the peak luminance of the sub-pixel W. In addition, the polygonal lines L32 and L33 represent the control of the peak luminance of the sub-pixels R, G, and B.

[0097] like Figure 9 As shown in , since the sub-pixels R, G, and B have an upper limit on the gain, the brightness level can be prevented from decreasing by setting the emission duty to 75% (Duty75%) in areas where the average pixel level is low. It should be noted that in areas where the average pixel level is high, the brightness levels are almost the same when the emission duty is 50% (Duty50%) and 75% (Duty75%).

[0098] In this way, the upper limit of the gain of sub-pixels R, G, and B is limited to a value lower than the upper limit of sub-pixel W. Therefore, highly saturated pixels have the following problem: even if the emission duty is reduced, the gain cannot be increased sufficiently to maintain saturation, and the brightness is reduced. Therefore, in this technology, in order to maintain the brightness balance between pixels with low saturation and pixels with high saturation, the lower limit of the emission duty is set according to the saturation level parameter.

[0099] Specifically, in the signal processing device 10 , the optimal duty value calculation unit 105 calculates the optimal light emission duty value using the saturation level detected by the saturation detection unit 102 so as to maintain the brightness balance between the portion with high saturation and the portion with low saturation.

[0100] Figure 10 An example of controlling the light emission duty according to the saturation level is shown. Figure 10, the horizontal axis shows the saturation level (Color_Sat_Lev), and the vertical axis represents the light emission duty value.

[0101] Figure 10 The figure shows that as the value on the horizontal axis increases toward the right, the saturation increases, and as the value on the vertical axis increases, the emission duty value increases. If the emission duty is reduced in a video with many areas with high saturation, the brightness balance will be lost due to the upper limit of the gain of the sub-pixels R, G, and B. Therefore, as shown by polygonal line L23, the lower limit value of the emission duty is set according to the saturation level, and in a video with many areas with high saturation, the emission duty is increased to maintain the brightness balance between pixels with high saturation and pixels with low saturation.

[0102] (According to APL control)

[0103] In an OLED display panel, as the grayscale becomes lower, the time required from application of a voltage to both ends of an OLED element until the amount of light emission reaches a predetermined amount has a greater influence on the driving duty.

[0104] Therefore, when the OLED display device performs black insertion driving as a measure to prevent blurring, the effective emission period in the low grayscale area is reduced, and as the emission duty is reduced, black clipping tends to occur. Black clipping is a state in which the brightness difference of the dark part cannot be fully expressed and is filled like a pure black color.

[0105] Figure 11 An example of gamma correction during black insertion driving is shown. Figure 11 In FIG, the horizontal axis represents the input level, and the vertical axis represents the output level.

[0106] exist Figure 11 In the figure, straight line L41 shows the target gamma value (2.2). Polygonal line L42 shows normal driving with a 100% duty cycle (Duty 100%) and a gain of 1 (Gain × 1). Polygonal line L43 shows black insertion driving with a 50% duty cycle (Duty 50%) and a doubled gain (Gain × 2).

[0107] focus on Figure 11 From the relationship between the straight line L41 and the polygonal lines L42 and L43 in the lower left area of FIG. 1 , it is clear that in the case of driving the OLED element, a lower gradation level has a greater influence on the driving duty due to the rising light emission characteristics.

[0108] Figure 12 An example of an effective light emitting period during normal driving and black insertion driving is shown. Figure 12, the horizontal axis represents time, and the vertical axis represents voltage level.

[0109] Figure 12 A in FIG. 5 shows voltage fluctuations of the OLED element during normal driving, and for each frame, the time after the voltage level shown by the waveform L51 exceeds the threshold voltage Vth is the effective light emitting period T1 . Figure 12 B in FIG. 1 shows voltage fluctuations of the OLED element during black insertion driving, and for each frame, the time after the voltage level shown by waveform L52 exceeds the threshold voltage Vth is the effective light-emitting period T2. The effective light-emitting period T2 during black insertion driving is shorter than the effective light-emitting period T1 during normal driving.

[0110] In this way, when driving an OLED element with black insertion, due to the rising emission characteristics, lower grayscale levels have a greater impact on the drive duty. Therefore, when black insertion driving is performed as a measure to prevent blurring, the effective emission period is reduced and the brightness reduction in low grayscale areas becomes significant. As the emission duty decreases, black clipping tends to occur.

[0111] Therefore, in the present technology, in the case of an image frame with a low average pixel level (APL) (a video in which the entire screen is dark), the lower limit value of the luminous duty cycle is controlled based on the average pixel level parameter, paying attention to the fact that the effect of improving the blur retention cannot be obtained, so that the deviation of the gamma correction is suppressed and black clipping at low grayscale levels is suppressed.

[0112] Specifically, in the signal processing device 10 , the optimum duty value calculation unit 105 calculates the optimum light emission duty value using the average pixel level (APL) detected by the APL detection unit 104 so that a decrease in brightness at lower gray levels is suppressed.

[0113] Figure 13 An example of controlling the light emission duty according to the average pixel level (APL) is shown. Figure 13 In the graph, the horizontal axis represents the average pixel level (Ave_Pix_Lev), and the vertical axis represents the luminous duty value.

[0114] Figure 13 The figure shows that as the value on the horizontal axis moves to the right, the video becomes brighter and has a higher average pixel level, and as the value on the vertical axis moves upward, the light duty value becomes higher. In dark video with a low average pixel level, if the light duty is reduced, black clipping tends to occur. Therefore, as shown by polygonal line L24, the lower limit value of the light duty is set according to the average pixel level. When the average pixel level is low, control is performed to increase the light duty. As the average pixel level decreases, the light duty value increases, thereby suppressing black clipping at lower grayscale levels.

[0115] (Offset Control)

[0116] In the above description, control of the light emission duty according to the average pixel level (APL) has been described as a measure against brightness reduction at low gray levels in the case of driving the OLED element with black insertion. However, other methods may be used.

[0117] For example, in the signal processing device 10 , the offset control unit 108 calculates an offset value related to the brightness of the video signal based on the lighting duty value calculated by the optimal duty value calculation unit 105 and adds the offset value to the video signal so that the brightness is corrected.

[0118] By controlling the offset value of the video signal according to the emission duty value in this way, a decrease in brightness at low grayscale levels is suppressed, and thus black clipping can be suppressed. It should be noted that here, it is also possible to consider correcting gamma correction by correcting brightness with an offset value.

[0119] (Peak current control)

[0120] Since the OLED display panel is configured by arranging multiple OLED elements in a two-dimensional manner, it is necessary to scan the black signal to turn off each OLED element. When performing black insertion driving, the light emitting area changes within one frame and the current fluctuates.

[0121] Therefore, in the case of a display where the load is concentrated on a specific scanning timing, there is a problem that the peak current increases by the amount of the average current×gain and exceeds the peak current limit value of the power supply circuit for driving the OLED element.

[0122] Figure 14 An example of current fluctuation in a power supply circuit for driving an OLED element is shown. Figure 14 , the horizontal axis represents time, and the vertical axis represents the EVDD current value.

[0123] exist Figure 14 In FIG, the polygonal line L61 shows the temporal fluctuation of the EVDD current value. Figure 14 , images I1 to I6 in one frame are arranged in time sequence, and correspond to the temporal fluctuation of the EVDD current value shown by the polygonal line L61.

[0124] It should be noted that the straight line L62 shows the peak current limit value, and is controlled so that the peak current does not exceed the limit value. In addition, the straight line L63 shows the average current limit value, and is controlled so that the average current does not exceed the limit value.

[0125] Image I is an image consisting of a monochrome window represented by a dot pattern and a black background. When black insertion driving is performed, the light-emitting area corresponding to the monochrome window in Image I changes as in Images I1 to I6 within a single image frame. At this time, the EVDD current value shown by polygonal line L61 fluctuates according to this light-emitting area.

[0126] In addition, Figure 14 In the image, frame FR represents an area within the frame displaying a black signal for black insertion. As indicated by images I1 to I6, black insertion is performed from the top to the bottom, with scanning progressing downward and the displayed signal updated from the top. In other words, the black insertion area in frame FR shifts downward.

[0127] Here, when the light-emitting area represented by the horizontal band of the dot pattern has a specific height such as images I1, I2, I6 in one frame, that is, in the case of a display with a load concentrated on a specific scanning timing, the peak current increases by the amount of the average current × gain, so that the EVDD current value shown by the solid line L61 exceeds the peak current limit value.

[0128] It should be noted that in the case where there is no light emitting area, such as image I4 in one frame, the EVDD current value is set to approximately 0.

[0129] In this way, even when black insertion is performed, the average current per frame can be set to the same value as when black insertion is not performed. However, since the light-emitting area changes within a frame, current fluctuations occur, and there is a problem of needing to suppress the current within the peak current value that the driver power supply circuit can tolerate. Therefore, in this technology, the method of calculating the current limit is corrected according to the gain used for brightness compensation, and control is performed so that the peak current becomes a certain value or less.

[0130] That is, in the present technology, the calculated value of the peak current is corrected according to the gain, and control of reducing the average current limit value can be performed according to the ratio of the gain exceeding the peak current limit value, so that even when the peak current where the load is concentrated is the maximum value, the peak current does not exceed the peak current limit value.

[0131] Specifically, in the signal processing device 10 , the peak current control unit 107 controls the peak current based on the gain calculated by the gain calculation unit 106 , thereby suppressing the peak current within the peak current limit value of the drive power circuit.

[0132] Figure 15 An example of peak current control is shown in Figure 15 , the horizontal axis represents time, and the vertical axis represents the EVDD current value.

[0133] exist Figure 15 In FIG. 1 , polygonal line L71 shows the temporal fluctuation of the EVDD current value when peak current control is not performed. Polygonal line L72 shows the temporal fluctuation of the EVDD current value when peak current control is performed. It should be noted that straight line L73 shows the peak current limit value. Furthermore, straight line L74 shows the average current limit value.

[0134] Here, the current value limit in the driving power supply circuit includes the limit on the average current value and the limit on the peak current value. In the case of not limiting the peak current, the peak current value increases by the maximum value of 1 / Duty (for example, in the case of Duty 50%, the increase is doubled), and the peak current exceeds the peak current limit value.

[0135] In order to keep the peak current within the peak current limit, control is required to reduce the gain of the entire display area. Figure 15 In the example shown in , the gain to be increased by luminance compensation during black insertion driving is controlled to a value expressed by the following equation (1).

[0136] Gain = Peak current limit value / Average current limit value. ..(1)

[0137] In this manner, without peak current control, the peak current would have exceeded peak current limit value L73, as indicated by polygonal line L71. However, by controlling the peak current, the peak current is controlled to fall within peak current limit value L73, as indicated by polygonal line L72. Thus, the reliability of the drive power supply circuit can be ensured.

[0138] (Configuration of Self-Luminous Display Device)

[0139] Figure 16 An example of the configuration of an embodiment of a self-luminous display device to which the technology of the present invention is applied is shown.

[0140] exist Figure 16 In the embodiment, the self-luminous display device 1 is configured as a television receiver or the like. The self-luminous display device 1 includes a signal input unit 111, a signal processing unit 112, a display panel driving unit 113, and a self-luminous display panel 114. It should be noted that the signal processing unit 112 corresponds to Figure 1 The signal processing device 10, and the display panel driving unit 113 corresponds to Figure 1 The panel driver 20.

[0141] The signal input unit 111 includes a tuner connected to an antenna, a communication module connectable to a communication network such as the Internet, an input interface conforming to a predetermined standard, and the like.

[0142] The signal input unit 111 provides the signal processing unit 112 with video signals of various types of content (such as broadcast content transmitted through terrestrial broadcasting, satellite broadcasting, etc., communication content transmitted via a communication network stream such as the Internet, and recorded content recorded on a recording medium such as an optical disc or a semiconductor memory or recorder).

[0143] The signal processing unit 112 performs predetermined video signal processing based on the video signal of the content supplied from the signal input unit 111. In this video signal processing, the video signal and a control signal for controlling the driving of the self-luminous display panel 114 are generated and supplied to the display panel driving unit 113. For example, the control signal includes parameters such as a light emission duty value (Duty), a gain (Gain), a current limit value (Cur_ratio), and an offset value (Offset).

[0144] The display panel drive unit 113 drives the self-luminous display panel 114 based on the video signal and the control signal supplied from the signal processing unit 112. The self-luminous display panel 114 is a display panel in which pixels including self-luminous elements are two-dimensionally arranged, and displays video according to the drive from the display panel drive unit 113.

[0145] An OLED display panel using an OLED element as a self-luminous element may be used as the self-luminous display panel 114. When an OLED display panel is used as the self-luminous display panel 114, the self-luminous display device 1 is an OLED display device.

[0146] It should be noted that Figure 16 In the configuration shown in , a minimum configuration is shown for simplicity of description, but other circuits and devices may be included, such as an audio signal processing circuit that processes an audio signal and a speaker that outputs audio according to the audio signal.

[0147] <2. Variants>

[0148] In the signal processing device 10, when the optimal duty value calculation unit 105 calculates the light emission duty value, it can use not only one of the four parameters (Detail_Lev, Color_Sat_Lev, Motion, and Ave_Pix_Lev) but also multiple parameters to calculate the light emission duty value. In addition, in the signal processing device 10, multiple control operations can be performed simultaneously, such as the current control performed by the peak current control unit 107 and the offset value control performed by the offset calculation unit 108.

[0149] In the above description, the case where the self-luminous display device 1 is a television receiver has been shown, but examples of electronic devices using the self-luminous display device 1 include display devices, personal computers and tablet computers, smart phones, mobile phones, digital cameras, head-mounted displays, and game consoles.

[0150] Furthermore, the self-luminous display device 1 can be used as a display unit for an in-vehicle device (such as a car navigation system or a rear seat monitor) or as a display unit for a wearable device (such as a watch or glasses). Note that examples of display devices include medical monitors, broadcast monitors, and displays for digital signage.

[0151] Note that in this specification, "OLED" can be interpreted as "organic EL." For example, an OLED display device can be considered an organic EL display device. Furthermore, since maintaining blur is also called motion blur, "maintaining blur" can be interpreted as "motion blur." Furthermore, since a video consists of multiple image frames, "video" can be interpreted as "image."

[0152] It should be noted that the embodiments of the present technology are not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present technology.

[0153] Furthermore, the effects described in this specification are merely examples and not limitations, and other effects may be exhibited.

[0154] It should be noted that the present technology can adopt the following configurations.

[0155] (1) A signal processing device comprising:

[0156] a detection unit configured to analyze a video signal of the content and detect an indicator related to maintaining blur;

[0157] a first calculating unit configured to calculate a light-emitting duty value of the self-luminous display panel based on the detected indicator; and

[0158] The second calculation unit is configured to calculate a gain for brightness compensation based on the calculated light emission duty value.

[0159] (2) The signal processing device according to (1), wherein

[0160] The detection unit detects the amount of motion of an object displayed on the self-luminous display panel, and

[0161] The first calculation unit calculates a light emission duty value according to the detected motion amount.

[0162] (3) The signal processing device according to (2), wherein

[0163] The first calculation unit decreases the light emission duty value as the detected motion amount increases, and

[0164] The second calculation unit increases the gain in response to the change in the light emission duty value.

[0165] (4) The signal processing device according to any one of (1) to (3), wherein

[0166] The detection unit detects the detail level of the video displayed on the self-luminous display panel, and

[0167] The first calculation unit calculates a light emission duty value according to the detected detail level.

[0168] (5) The signal processing device according to (4), wherein

[0169] The first calculation unit decreases the light emission duty value as the detected detail level increases, and

[0170] The second calculation unit increases the gain in response to the change in the light emission duty value.

[0171] (6) The signal processing device according to any one of (1) to (5), wherein

[0172] The detection unit detects the saturation level of the video displayed on the self-luminous display panel, and

[0173] The first calculation unit calculates a light emission duty value according to the detected saturation level.

[0174] (7) The signal processing device according to (6), wherein

[0175] The first calculation unit sets a limit on a lower limit value of the light emission duty value according to the detected saturation level.

[0176] (8) The signal processing device according to any one of (1) to (7), wherein

[0177] The detection unit detects the average pixel level of the video signal, and

[0178] The first calculation unit calculates a light emission duty value according to the detected average pixel level.

[0179] (9) The signal processing device according to (8), wherein

[0180] The first calculation unit sets a limit on a lower limit value of the light emission duty value when the detected average pixel level is less than a certain level, and increases the light emission duty value as the average pixel level decreases.

[0181] (10) The signal processing device according to any one of (1) to (9), further comprising:

[0182] The control unit is configured to control a current flowing through a self-luminous element arranged in the self-luminous display panel according to the gain so that the current is suppressed within an allowable peak current by the power supply circuit.

[0183] (11) The signal processing device according to (10), wherein

[0184] In the case where the light emitting area of the self-luminous display panel changes within one frame of a video and the peak current becomes maximum when current fluctuation occurs, the control unit controls the peak current not to exceed the peak current limit value.

[0185] (12) The signal processing device according to (11), wherein

[0186] The control unit performs control so that the gain becomes a value obtained by dividing the peak current limit value by the average current limit value.

[0187] (13) The signal processing device according to any one of (1) to (12), further comprising:

[0188] The third calculation unit is configured to calculate an offset value regarding the brightness of the video signal according to the light emission duty value.

[0189] (14) The signal processing device according to (13), wherein

[0190] The reduction in brightness of low gray levels is corrected by the offset value.

[0191] (15) The signal processing device according to any one of (1) to (14), wherein

[0192] The light emission duty is reduced by black insertion driving in which a black display period is provided during a display period for displaying the same video.

[0193] (16) The signal processing device according to (15), wherein

[0194] The gain is obtained by the inverse of the light duty value.

[0195] (17) The signal processing device according to any one of (1) to (16), wherein

[0196] The self-luminous display panel has first subpixels generating red (R) light, second subpixels generating green (G) light, third subpixels generating blue (B) light, and fourth subpixels generating white (W) light arranged in a two-dimensional manner.

[0197] (18) The signal processing device according to (17), wherein

[0198] The pixel includes an organic light emitting diode (OLED) element as a self-luminous element.

[0199] (19) A signal processing method comprising:

[0200] Through the signal processing device,

[0201] analyzing a video signal of the content and detecting indicators related to maintaining blur;

[0202] Calculating a light-emitting duty value of the self-luminous display panel based on the detected index; and

[0203] A gain for brightness compensation is calculated based on the calculated light emission duty value.

[0204] (20) A display device comprising:

[0205] a signal processing unit configured to process a video signal of the content;

[0206] A self-luminous display panel configured to display a video of the content; and

[0207] The display panel driving unit is configured to drive the self-luminous display panel based on the video signal from the signal processing unit, wherein

[0208] The signal processing unit includes

[0209] a detection unit configured to analyze a video signal of the content and detect an indicator related to maintaining blur;

[0210] a first calculating unit configured to calculate a light-emitting duty value of the self-luminous display panel based on the detected indicator; and

[0211] a second calculating unit configured to calculate a gain for brightness compensation based on the calculated light emission duty value; and

[0212] The display panel driving unit drives the self-luminous display panel based on the light emission duty value and the gain calculated by the signal processing unit.

[0213] Reference Signs List

[0214] 1 Self-luminous display device

[0215] 10Signal processing device

[0216] 20 panel drivers

[0217] 30 signal lines

[0218] 40 control lines

[0219] 100 detection units

[0220] 101 Image Flatness Detection Unit

[0221] 102 saturation detection unit

[0222] 103 motion detection unit

[0223] 104APL detection unit

[0224] 105 optimal duty value calculation unit

[0225] 106 gain calculation unit

[0226] 107 Peak Current Control Unit

[0227] 108 offset calculation unit

[0228] 111 signal input unit

[0229] 112 signal processing unit

[0230] 113 display panel drive unit

[0231] 114 self-luminous display panel.

Claims

1. A signal processing device, comprising: a detection unit configured to analyze a spatial resolution of a video signal of contents of a plurality of frames and detect an index related to preserving blur, wherein the detected index represents an edge portion included in the video signal, and the detected index is based on the analysis of the spatial resolution of the plurality of frames included in the video signal; A first calculation unit is configured to calculate a light-emitting duty value of a self-luminous display panel based on the detected indicator, wherein the self-luminous display panel includes a plurality of pixels, each pixel includes a group of sub-pixels, The calculated luminous duty cycle value for black insertion driving is lower than the calculated luminous duty cycle value for normal driving, and In the black insertion driving, a display time of a video is shortened by a black display period during a display period of the video, and when a calculated light emission duty cycle value is less than 100%, a peak luminance of a brightest sub-pixel in one of the plurality of pixels exceeds a combined peak luminance of remaining sub-pixels in the one of the plurality of pixels at a portion where an average pixel level of the video signal is low; and a second calculating unit configured to calculate a gain for brightness compensation based on the calculated light-emission duty value; The calculated gain for black insertion driving is greater than the calculated gain for normal driving.

2. The signal processing device according to claim 1, wherein The detection unit detects a motion amount of an object displayed on the self-luminous display panel, and The first calculation unit calculates the light emission duty value according to the detected motion amount.

3. The signal processing device according to claim 2, wherein The first calculation unit reduces the light emission duty value as the detected motion amount increases, and The second calculation unit increases the gain in response to a decrease in the light emission duty value. The signal processing device according to claim 1 , wherein The detection unit detects a detail level of a video displayed on the self-luminous display panel, and The first calculation unit calculates the light emission duty value according to the detected detail level. The signal processing device according to claim 4 , wherein The first calculation unit reduces the light emission duty value as the detected detail level increases, and The second calculation unit increases the gain in response to a change in the light emission duty value. The signal processing device according to claim 1 , wherein The first calculation unit sets a limit on a lower limit value of the light emission duty value according to a detected saturation level of a video displayed on the self-luminous display panel.

7. The signal processing device according to claim 1, wherein The detection unit detects the average pixel level of the video signal, and The first calculation unit calculates the light emission duty value according to the detected average pixel level.

8. The signal processing device according to claim 7, wherein: When the detected average pixel level is less than a certain level, the first calculation unit sets a limit on a lower limit value of the light emission duty value, and increases the light emission duty value as the average pixel level decreases.

9. The signal processing apparatus according to claim 1, further comprising: A control unit is configured to control a current flowing through a self-luminous element arranged in the self-luminous display panel according to the gain so as to suppress a peak current within an allowable peak current value of a power supply circuit based on the calculated gain.

10. The signal processing device according to claim 9, wherein In a case where the peak current becomes maximum when the light emitting area of the self-luminous display panel changes within one frame of the video and current fluctuation occurs, the control unit controls the peak current not to exceed a peak current limit value. The signal processing device according to claim 10 , wherein The control unit performs control so that the gain becomes a value obtained by dividing the peak current limit value by an average current limit value.

12. The signal processing apparatus according to claim 1, further comprising: A third calculation unit is configured to calculate an offset value regarding the brightness of the video signal based on the calculated light emission duty value.

13. The signal processing device according to claim 12, wherein The brightness of low gray levels is reduced based on the calculated offset value.

14. The signal processing device according to claim 1, wherein The gain is calculated as the inverse of the light-emission duty value.

15. The signal processing device according to claim 1, wherein The group of subpixels includes a first subpixel generating red (R) light, a second subpixel generating green (G) light, a third subpixel generating blue (B) light, and a fourth subpixel generating white (W) light, and the plurality of pixels are arranged in a two-dimensional manner. The signal processing device according to claim 15 , wherein Each of the plurality of pixels includes an organic light emitting diode (OLED) element as a self-luminous element.

17. A signal processing method, comprising: Through the signal processing device, analyzing a spatial resolution of a video signal of contents of a plurality of frames and detecting an indicator related to preserving blur, wherein the detected indicator represents an edge portion included in the video signal, and the detected indicator is based on the analysis of the spatial resolution of the plurality of frames included in the video signal; Calculating a light-emitting duty cycle of a self-luminous display panel based on the detected indicator, wherein the self-luminous display panel includes a plurality of pixels, each pixel includes a group of sub-pixels, The calculated luminous duty cycle value for black insertion driving is lower than the calculated luminous duty cycle value for normal driving, and In the black insertion driving, a display time of a video is shortened by a black display period during a display period of the video, and when a calculated light emission duty cycle value is less than 100%, a peak luminance of a brightest sub-pixel in one of the plurality of pixels exceeds a combined peak luminance of remaining sub-pixels in the one of the plurality of pixels at a portion where an average pixel level of the video signal is low; and A gain for brightness compensation is calculated based on the calculated light emission duty value, wherein the calculated gain for black insertion driving is greater than the calculated gain for normal driving.

18. A display device comprising: a signal processing unit configured to process a video signal of the content; a self-luminous display panel configured to display a video of the content; as well as A display panel driving unit is configured to drive the self-luminous display panel based on the video signal from the signal processing unit, wherein The signal processing unit includes a detection unit configured to analyze spatial resolutions of a video signal of the content of a plurality of frames and detect an index related to preserving blur, wherein the detected index represents an edge portion included in the video signal, and the detected index is based on the analysis of the spatial resolutions of the plurality of frames included in the video signal; A first calculation unit is configured to calculate a light-emitting duty value of the self-luminous display panel based on the detected indicator, wherein the self-luminous display panel includes a plurality of pixels, each pixel includes a group of sub-pixels, The calculated luminous duty cycle value for black insertion driving is lower than the calculated luminous duty cycle value for normal driving, and In the black insertion driving, a display time of a video is shortened by a black display period during a display period of the video, and when a calculated light emission duty cycle value is less than 100%, a peak luminance of a brightest sub-pixel in one of the plurality of pixels exceeds a combined peak luminance of remaining sub-pixels in the one of the plurality of pixels at a portion where an average pixel level of the video signal is low; and a second calculating unit configured to calculate a gain for brightness compensation based on the calculated light-emitting duty value, wherein the calculated gain for black insertion driving is greater than the calculated gain for normal driving; And the display panel driving unit drives the self-luminous display panel based on the light emission duty value and the gain calculated by the signal processing unit.

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