Dimming processing equipment and timing controller

Abstract

The present invention relates to a dimming processing device and a timing controller. Embodiments enable the brightness of a backlight unit to change naturally and smoothly, and can reduce flicker by changing the dimming value between frames through a hybrid function including multiple functions with different characteristics.

Description

Technical Field

[0001] The present disclosure relates to a dimming processing technique for visually and naturally changing the dimming value of a backlight between frames. Background Art

[0002] Among the various components that make up an electronic device, the component with the highest power consumption is the display device. During the time when information is provided to the user, the display device remains in an on state and continues to emit light during the time the display device is on, resulting in higher power consumption in the display device than in other components of the electronic device.

[0003] For this reason, electronic device manufacturers are continuously conducting research and development to reduce the power consumption of display devices, a typical example of which is a technology for switching a display device to a standby mode or turning on only a portion of a display panel.

[0004] However, since these technologies aim to reduce the power consumption of the display device by actually limiting the user environment to a certain extent, these technologies inevitably bring some inconvenience to the user.

[0005] On the other hand, technology capable of reducing power consumption of a display device without changing a user environment or while providing a user environment involving minor changes that are negligible to the user is under development, and typical examples of the technology are local dimming technology and global dimming technology.

[0006] Local dimming is a technology for partially driving the backlight at different brightnesses. According to local dimming, the display panel can be divided into several areas, and a plurality of backlight units (BLUs) can emit light to the divided areas at different brightnesses. Here, the huge difference in the brightness of the backlight units emitting light to the respective areas may cause artifacts, such as occlusion artifacts or halo artifacts. Filtering can be performed during image processing to remove artifacts, but the brightness of the backlight unit may increase during filtering. In particular, in the case where the brightness of the peripheral backlight units is high, the brightness of the backlight unit may also increase. As the brightness of the backlight unit increases, the power consumption also increases proportionally thereto. Although the power consumption of the backlight unit is reduced compared to the state before local dimming is applied, the power consumption becomes slightly higher as filtering is performed, so it may not be possible to reduce the power consumption more effectively.

[0007] In addition, if the brightness of the backlight unit emitting light varies greatly over time, that is, if there is a large difference in the brightness of the backlight unit between the first time and the second time, flicker may occur. Although filtering is performed during image processing to remove the above defects, the filtering process may cause some problems.

[0008] First, an infinite impulse response (IIR) filter can be used for filtering, but an IIR filter cannot obtain the exact target brightness of the backlight unit. In some cases, an IIR filter can improve the accuracy of obtaining the target brightness by interpolating between the current brightness and the target brightness to determine an intermediate brightness. Despite this approach, due to the problem of floating operations in the hardware, the IIR filter may have difficulty obtaining the exact target brightness.

[0009] Next, using an IIR filter for filtering can make it difficult to control the time required to reach the target brightness of the backlight unit. If the IIR filter performs interpolation, the time required to achieve the target brightness of the backlight unit can be set. However, there may be temporal differences in brightness, which can cause unnatural changes such as flickering that the human eye may perceive.

[0010] In this regard, the present embodiment provides a dimming processing technique that provides a visually and naturally perceived change in the brightness of a backlight unit while adjusting the time required to reach a target brightness of the backlight unit. Summary of the Invention

[0011] In this context, the present embodiment provides a dimming processing technique for changing a dimming value between frames using a hybrid function including a plurality of functions having different characteristics.

[0012] On the other hand, the present embodiment provides a dimming processing technology for quickly changing the dimming value in an initial interval of the dimming time in which the dimming value is changed, and slowly changing the dimming value in a subsequent interval of the dimming time.

[0013] To this end, in one aspect, the present disclosure provides a dimming processing device according to an embodiment, for adjusting the dimming value of a backlight, the dimming processing device comprising: a dimming value receiving circuit, configured to receive a first dimming value and a second dimming value; and a dimming value adjusting circuit, configured to change the dimming value according to a first function in a first interval of a dimming change time, and to change the dimming value according to a second function different from the first function in a second interval of the dimming change time, the dimming value adjusting circuit being configured to change the dimming value from the first dimming value to the second dimming value.

[0014] When the frame changes from a first frame to a second frame, the dimming value adjustment circuit may change the dimming value from the first dimming value to the second dimming value.

[0015] A change rate of the dimming value according to the first function in the first interval is higher than a change rate of the dimming value according to the second function in the second interval.

[0016] The first interval may be shorter than the second interval.

[0017] The dimming value adjustment circuit may change the dimming value to a third dimming value between the first dimming value and the second dimming value according to the first function.

[0018] The dimming value adjustment circuit may change the dimming value from a third dimming value between the first dimming value and the second dimming value according to the second function.

[0019] The dimming value adjustment circuit may change the dimming value to a third dimming value between the first dimming value and the second dimming value according to the first function, and may change the dimming value from the third dimming value according to the second function.

[0020] The first function and the second function may be functions of time, and the first function may have a slope that decreases with time in the first interval.

[0021] The first interval may include at least a portion of an initial interval of the dimming change time, and the second interval may include at least a portion of a subsequent interval of the dimming change time.

[0022] The first function may be a non-linear function, and the second function may be a linear function.

[0023] The first function may have a slope that varies with time, and the second function may have a constant slope with time.

[0024] The rate of change of the dimming value may vary over time in the first interval and may be constant over time in the second interval.

[0025] According to another embodiment, a dimming processing device is provided for adjusting the dimming value of a backlight. The dimming processing device may include: a dimming value receiving circuit configured to receive a target dimming value; and a dimming value adjusting circuit configured to change the dimming value according to the target dimming value during a dimming change time in each frame, wherein, if the frame changes, the dimming value adjusting circuit may be configured to change the dimming value at a first change rate in an initial interval of the dimming change time, and to change the dimming value at a second change rate lower than the first change rate in a subsequent interval of the dimming change time.

[0026] The first rate of change may vary over time in the initial interval and the second rate of change may be constant over time in the subsequent interval.

[0027] The dimming value receiving circuit can receive a first target dimming value for determining the brightness of the backlight in a first frame and a second target dimming value for determining the brightness of the backlight in a second frame, and the dimming value adjustment circuit can change the dimming value from the first target dimming value to a predetermined dimming value between the first target dimming value and the second target dimming value at the first change rate during the initial interval.

[0028] The dimming value adjustment circuit may change the dimming value from the predetermined dimming value to the second target dimming value at the second change rate during the subsequent interval.

[0029] Another embodiment provides a timing controller for outputting a dimming control signal of a backlight, the timing controller may include: a dimming value adjustment circuit, configured to change the dimming value of the backlight according to a first function in a first interval of the dimming change time, and to change the dimming value according to a second function different from the first function in a second interval of the dimming change time, the dimming value adjustment circuit being configured to change the dimming value from the first dimming value to the second dimming value; and a dimming output circuit, configured to apply the dimming value to the dimming control signal and output the dimming control signal.

[0030] The first dimming value and the second dimming value may be generated according to a control signal received from a host.

[0031] The dimming output circuit may send the dimming control signal to a backlight driving device for adjusting the brightness of the backlight.

[0032] A change rate of the dimming value in the first interval may be higher than a change rate of the dimming value in the second interval.

[0033] As described above, according to the present embodiment, by adjusting the rate for changing the brightness of the backlight unit, the accurate target brightness of the backlight unit can be obtained without flickering or shooting of the brightness of the backlight unit.

[0034] In addition, according to the present embodiment, it is possible to smoothly and naturally change the brightness of the backlight unit and reduce flickering of brightness by reducing the rate for changing the brightness of the backlight unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a diagram illustrating a configuration of a display device according to an embodiment.

[0036] Figure 2 is a diagram showing a configuration of an image data processing apparatus according to an embodiment.

[0037] Figure 3FIG. 4 is a diagram illustrating an example of reducing a dimming value by analyzing luminance distribution of pixels according to an embodiment.

[0038] Figure 4 is a diagram illustrating actual measurements of pixel brightness reduction in response to a reduction in dimming value according to an embodiment.

[0039] Figure 5 is a diagram illustrating an example of calculating a compensation gain according to an embodiment.

[0040] Figure 6 is a flowchart illustrating the operation of the image data processing apparatus according to the embodiment.

[0041] Figure 7 is a diagram illustrating a configuration of a dimming processing device included in an image data processing device according to another embodiment.

[0042] Figure 8 is a diagram illustrating a detailed configuration of a filter circuit included in a dimming processing device according to another embodiment.

[0043] Figure 9 is a diagram illustrating a change in the duty ratio of a PWM signal between frames according to another embodiment.

[0044] Figure 10 : is a diagram showing an example for explaining a change in a dimming value between frames.

[0045] Figure 11 : is a diagram showing a first example for explaining a change in a dimming value between frames according to another embodiment.

[0046] Figure 12 : is a diagram showing a second example for explaining a change in a dimming value between frames according to another embodiment.

[0047] Figure 13 : is a diagram showing a third example for explaining a change in a dimming value between frames according to another embodiment. DETAILED DESCRIPTION

[0048] refer to Figure 1 The display device 100 may include a host 140, an image data processing device 110, a data driving device 150, a gate driving device 160, a display panel 130, a backlight driving device 120, and the like.

[0049] The host 140 may recognize a user operation and may generate image data or a dimming control signal according to the user operation.

[0050] In the display device 100, image data may be converted into various forms. Hereinafter, the image data generated and transmitted by the host 140 will be referred to as "raw image data" RGB in order to distinguish the image data from the converted image data, and the image data generated and transmitted by the image data processing device 110 will be referred to as "converted image data" RGB'. In addition, the dimming value included in the dimming control signal may be adjusted in the display device 100. Hereinafter, the dimming control signal generated and transmitted by the host 140 will be referred to as "unadjusted dimming control signal" DMS in order to distinguish the dimming control signal from the adjusted dimming control signal, and the dimming control signal generated and transmitted by the image data processing device 110 will be referred to as "adjusted dimming control signal" DMS'.

[0051] Referring to the signal flow, image data is generated by the host 140, converted by the image data processing device 110, and then transmitted to the data driving device 150. In addition, a dimming control signal is generated by the host 140, adjusted by the image data processing device 110, and then transmitted to the backlight driving device 120.

[0052] The image data processing device 110 converts image data and adjusts a dimming control signal.

[0053] The image data processing device 110 can analyze the raw image data RGB on the plurality of pixels P arranged in the display panel 130, and can calculate representative brightness values ​​of the plurality of pixels P. Since the plurality of pixels P have brightness values ​​different from each other, the image data processing device 110 calculates a representative brightness value representing the plurality of pixels P. The representative brightness value can be, for example, an average brightness value of the plurality of pixels P. Alternatively, the representative brightness value can be, for example, a brightness value that appears most frequently in the plurality of pixels P, or can be its maximum brightness value. The image data processing device 110 can use a cumulative density function (CDF) algorithm or an average pixel level (APL) algorithm to calculate the representative brightness values ​​of the plurality of pixels P.

[0054] Image data processing device 110 can calculate an adjusted dimming value for driving backlight 132 based on the representative brightness value or a value obtained by modifying the representative brightness value according to a predetermined configuration. Here, the dimming value can be understood as a dimming brightness value. The higher the dimming value, the higher the brightness value of backlight 132. For example, if the dimming value is 100%, backlight 132 can be driven at maximum brightness, and if the dimming value is 0%, backlight 132 can be driven at minimum brightness or turned off.

[0055] The image data processing device 110 may reduce the adjusted dimming value of the backlight 132 as the representative brightness value decreases. In other words, the image data processing device 110 may reduce the brightness of the backlight 132 as the representative brightness value decreases.

[0056] The image data processing device 110 can convert the raw RGB image data to compensate the grayscale value of each pixel according to the adjusted dimming value. To compensate for the grayscale value, the image data processing device 110 can calculate a factor called "gain" and use this gain to convert the raw RGB image data. For example, the image data processing device 110 can convert the raw RGB image data so that the grayscale value of each pixel increases as the adjusted dimming value decreases. Here, the gain can have the characteristic of increasing the grayscale value.

[0057] The image data processing device 110 may generate an adjusted dimming control signal DMS′ according to the adjusted dimming value, and may output the adjusted dimming control signal DMS′ to the backlight driving device 120 .

[0058] On the other hand, a plurality of pixels P may be arranged on the display panel 130, and data lines and gate lines connected to the plurality of pixels P may be arranged on the display panel 130. The gate driving device 160 may transmit a scan signal SS to the gate line, thereby connecting each pixel P to the data line, and the data driving device 150 may supply a data voltage Vdata corresponding to image data to the data line, thereby driving each pixel P.

[0059] The image data processing device 110 may transmit a gate control signal GCS to the gate driving device 160 and may transmit a data control signal DCS to the data driving device 150, thereby controlling the driving timing of each pixel P. In this regard, the gate driving device 160 may be referred to as a "gate driver IC (GDIC)", the data driving device 150 may be referred to as a "source driver IC (SDIC)", and the image data processing device 110 may be referred to as a "timing controller (TCON)".

[0060] The backlight 132 may be disposed in the background of the display panel 130 , and the backlight 132 may be driven by the backlight driving device 120 .

[0061] The backlight driving device 120 may control the brightness of a light source constituting the backlight 132. The light source may be provided by, for example, a fluorescent lamp (FL) type or a light emitting diode (LED) type.

[0062] The backlight driving device 120 may control the dimming of the backlight 132. For example, the backlight driving device 120 may control the dimming of the backlight 132 using an analog dimming scheme for reducing the amount of power PBL supplied to the backlight 132 while continuously driving the backlight 132. As another example, the backlight driving device 120 may control the dimming of the backlight 132 using a pulse width modulation (PWM) scheme for adjusting the ratio of on-time to off-time while discontinuously driving the backlight 132. According to an embodiment, the PWM scheme may be a method for controlling the brightness of the backlight using the amplitude of a voltage charged to a capacitor or the like by a PWM signal.

[0063] In the analog dimming scheme, the dimming control signal DMS or DMS′ may be implemented in the form of an analog voltage or an analog current, and in the PWM scheme, the dimming control signal DMS or DMS′ may be implemented in the form of a PWM signal.

[0064] Figure 2 is a diagram showing a configuration of an image data processing apparatus according to an embodiment.

[0065] refer to Figure 2 The image data processing device 110 may include an image analysis circuit 210, a dimming value calculation circuit 220, a filtering circuit 230, a pixel analysis circuit 240-1, a signal analysis circuit 240-2, a dimming control circuit 250, a dimming output circuit 260, a gain compensation circuit 270, a gain calculation circuit 280 and a data conversion circuit 290.

[0066] The image analysis circuit 210 may receive a video image including a plurality of regions, each of which includes a plurality of pixels. The backlight 132 may adjust dimming so that each region of the video image has a different dimming value.

[0067] The image analysis circuit 210 can analyze the raw RGB image data on the video image and calculate a representative brightness value for each region. The image analysis circuit 210 can calculate representative brightness values ​​for the raw R image data, raw G image data, and raw B image data to generate appropriate dimming values ​​for local dimming. The representative brightness value can include an average pixel level (APL). The representative brightness value can include an average value, a median value, or a value obtained through a histogram or pooling.

[0068] For example, the image analysis circuit 210 may use the maximum value among the original R image data, the original G image data, and the original B image data as the representative brightness value. Alternatively, the image analysis circuit 210 may use a value obtained by applying appropriate weights to the original R image data, the original G image data, and the original B image data and summing them as the representative brightness value. Alternatively, the image analysis circuit 210 may use a value obtained by mapping the original image data RGB onto a predetermined curve as the representative brightness value.

[0069] The dimming value calculation circuit 220 can calculate the dimming value. The dimming value calculation circuit 220 can calculate the initial dimming value DMV of each area based on the representative brightness value. The dimming value calculation circuit 220 can use a logarithmic function, an exponential function, or a user function to calculate the initial dimming value DMV representing the brightness value.

[0070] The filtering circuit 230 can filter the dimming value. The filtering circuit 230 can adjust the initial dimming value DMV by filtering to generate a filtered dimming value DMV'. The filtering circuit 230 can control the difference in the initial dimming values ​​DMV that are different between multiple areas of the video image. Generally, if the initial dimming value DMV in one area is smaller than the initial dimming value DMV in the adjacent area, the filtering circuit 230 can increase the initial dimming value DMV of the one area, thereby reducing the difference between them. Alternatively, if the initial dimming value DMV in one area is larger than the initial dimming value DMV in the adjacent area, the filtering circuit 230 can reduce the initial dimming value DMV of the one area, thereby reducing the difference between them. Adjusting the difference in the initial dimming values ​​(DMV) between multiple areas as described above can be understood as spatial filtering. Therefore, the filtering circuit 230 can prevent artifacts caused by the difference.

[0071] The filtering circuit 230 may adjust the dimming value using the weighted sum. The filtering circuit 230 may receive the weighted sum as feedback and may generate a new weighted sum, thereby performing a stable filtering operation.

[0072] The pixel analysis circuit 240-1 can analyze the brightness distribution of multiple pixels in each area. The pixel analysis circuit 240-1 can determine whether the brightness distribution of the pixels in each area is weighted toward low brightness. The pixel analysis circuit 240-1 can send the results of the pixel brightness distribution analysis to the dimming control circuit 250. The results of the pixel brightness distribution analysis can be reflected in the adjustment of the dimming value. For example, if the brightness distribution of the pixels in a certain area is weighted toward low brightness, the dimming control circuit 250 can adjust the filtered dimming value DMV' to low.

[0073] The pixel analysis circuit 240-1 may use a histogram to analyze the brightness distribution of the pixels. The pixel analysis circuit 240-1 may compare the number of low-brightness pixels with the number of high-brightness pixels based on the histogram results. Alternatively, the pixel analysis circuit 240-1 may receive a representative brightness value calculated by the image analysis circuit 210 as feedback and use the representative brightness value to determine the brightness distribution of the pixels.

[0074] The signal analysis circuit 240-2 can analyze the input signal used as the dimming control signal. For example, the dimming control signal can be implemented in the form of a PWM signal, and the backlight can be driven to a ratio corresponding to the on-time in the PWM signal. Here, the PWM signal can correspond to the input dimming control signal DMS analyzed by the signal analysis circuit 240-2. The signal analysis circuit 240-2 can analyze the characteristics of the PWM signal (for example, frequency, period, level or duty cycle). The signal analysis circuit 240-2 can send the result of analyzing the input dimming control signal DMS to the dimming control circuit 250. The result of analyzing the input dimming control signal DMS can be reflected in the adjustment of the dimming value.

[0075] The dimming control circuit 250 may finally determine the dimming value. The dimming control circuit 250 may apply the result of analyzing the brightness distribution of the pixels and the result of analyzing the input dimming control signal DMS to the filtered dimming value DMV′.

[0076] If the brightness distribution of pixels in a region is weighted toward low brightness, the dimming control circuit 250 may reduce the dimming value of the region to reduce the brightness of the backlight in the region. Accordingly, the dimming control circuit 250 may calculate an adjusted dimming value DMV' based on the filtered dimming value DMV'. The dimming control circuit 250 may send the adjusted dimming value DMV' to the dimming output circuit 260.

[0077] The dimming control circuit 250 may change the dimming value. The dimming control circuit 250 may compare the dimming value with a target dimming value and may gradually change the dimming value so that the dimming value reaches the target dimming value after a predetermined transition time.

[0078] The dimming output circuit 260 can convert the dimming value into a dimming control signal and output the dimming control signal to the backlight driving device. The dimming output circuit 260 can convert the adjusted dimming value DMV" into an adjusted dimming control signal DMS'. Preferably, the input dimming control signal DMS and the adjusted dimming control signal DMS' are of the same type. To this end, the dimming output circuit 260 must control the period or frequency of the adjusted dimming control signal DMS' to match the period or frequency of the input dimming control signal DMS.

[0079] The gain calculation circuit 280 can calculate a gain for compensating the raw image data RGB based on the dimming value. The gain calculation circuit 280 can receive the adjusted dimming value DMV' from the dimming control circuit 250 and calculate a gain for compensating the raw image data RGB based on the adjusted dimming value DMV'. Specifically, the gain Q can be a factor required to generate the same brightness for each pixel despite changes in the grayscale values ​​of the raw image data RGB and the filtered dimming value DMV'.

[0080] The gain compensation circuit 270 may compensate for the gain. The gain compensation circuit 270 may consider various situations in order to compensate for the gain.

[0081] In a first example, the gain compensation circuit 270 may compensate for a phenomenon in which the rate of change of the dimming value and the rate of change of the brightness of the pixel vary according to the pixel level. Hereinafter, the pixel level may be a concept of a grayscale value or brightness of image data including one pixel. In order to compensate for the difference caused by the fact that the ratio of the adjustment ratio of the brightness of the pixel relative to the adjustment ratio of the adjusted dimming value DMV″ varies according to the pixel level, the gain compensation circuit 270 may calculate a compensation gain Qc. For example, the gain compensation circuit 270 may calculate a compensation gain Qc that is used to compensate for the difference between the reduction rate of the brightness and the reduction rate of the adjusted dimming value DMV″.

[0082] For example, in a first pixel having a first pixel level, a ratio of a reduction rate of the pixel's brightness to a reduction rate of the adjusted dimming value DMV' may be greater than 1, but in a second pixel having a second pixel level, a ratio of a reduction rate of the pixel's brightness to a reduction rate of the adjusted dimming value DMV' may be less than 1. Therefore, the compensation gain Qc of the first pixel level and the compensation gain Qc of the second pixel level may be different from each other.

[0083] The gain compensation circuit 270 may calculate the compensation gain Qc using a lookup table (LUT) or a formula. The lookup table or formula may apply the actual situation of the change in the ratio of the reduction rate of the brightness of the pixel to the reduction rate of the adjusted dimming value DMV". The lookup table may be configured as a compensation gain Qc corresponding to all pixel levels. The formula may be configured as a compensation gain Qc that reflects factors that occur in the process of manufacturing the panel and measuring its brightness.

[0084] In a second example, the gain compensation circuit 270 can compensate for the fact that the brightness of a pixel corresponding to a dimming value varies depending on the pixel's location and distance from the backlight. The gain compensation circuit 270 can obtain information related to the pixel's brightness using a Gaussian function or a combination of linear polynomial functions, quadratic polynomial functions, etc., based on the sampling point. The gain compensation circuit 270 can calculate a compensation gain Qc to compensate for the fact that the brightness of a pixel corresponding to the adjusted dimming value DMV" varies depending on the pixel's location and distance from the backlight.

[0085] The gain calculation circuit 280 may ultimately determine a gain for compensating the original image data RGB according to the adjusted dimming value DMV″. The gain calculation circuit 280 may ultimately determine the gain Q by reflecting the compensation gain Qc obtained in the first example or the compensation gain Qc obtained in the second example.

[0086] The gain calculation circuit 280 may use an algorithm for ultimately determining the gain. If the original image data RGB is in a linear domain, the gain calculation circuit 280 may determine the gain using a formula that simply applies the gain. Alternatively, if the original image data RGB is in a nonlinear domain, the gain calculation circuit 280 may determine the gain using a formula obtained by simply applying a combination of a gain formula and a gamma curve. In this process, if a high pixel-level gain outside the permissible range of the panel is applied, the gain calculation circuit 280 may perform operations for appropriately adjusting the gain and applying the same gain to each of the R, G, and B channels to prevent degradation.

[0087] The data conversion circuit 290 may generate image data RGB′ converted from the original image data RGB using the gain. The data conversion circuit 290 may generate converted image data RGB′ by applying the finally determined gain Q to the R image data, the G image data, and the B image data.

[0088] Figure 3 FIG. 4 is a diagram illustrating an example of reducing a dimming value by analyzing luminance distribution of pixels according to an embodiment.

[0089] Figure 3 An example is shown in which the pixel analysis circuit 240 - 1 determines the amount of reduction of the dimming value by analyzing the brightness distribution of the pixels.

[0090] The pixel analysis circuit 240 - 1 may identify brightness distributions of multiple regions of a video image, and if the brightness distribution of one region corresponds to low brightness, the dimming value of the region may be reduced, thereby reducing power consumption of the backlight.

[0091] The pixel analysis circuit 240-1 can perform brightness distribution analysis on pixels in an area, thereby obtaining a curve indicating the relationship between the number of pixels and the pixel level. Here, the number of pixels can be histogram data or NCDF (Normalized Cumulative Density Function) data.

[0092] For example, if the first region has a low brightness distribution and if the second region has a high brightness distribution, the brightness distribution of the first region may have a first curve I, and the brightness distribution of the second region may have a second curve II. On the horizontal axis representing the pixel level, the pixel level may change from a high level to a low level as it progresses from left to right. Since the first region includes a large number of low-brightness pixels, the first curve I may have a steep rise at the low level and a gentle slope at the high level. Since the second region includes a large number of high-brightness pixels, the second curve II may have a gentle slope at the low level and a steep rise at the high level.

[0093] When a specific number of pixels is configured as a threshold value Th on the vertical axis indicating the number of pixels, the pixel analysis circuit 240-1 can obtain the pixel levels at the points where the respective curves meet the threshold value Th. The pixel analysis circuit 240-1 can obtain a first pixel level VAL_1 and a second pixel level VAL_2, where the first pixel level is the pixel level at the point where the first curve I meets the threshold value Th, and the second pixel level is the pixel level at the point where the second curve II meets the threshold value Th. Since the pixel level changes from a high level to a lower level as progressing from left to right on the horizontal axis indicating the pixel level, the first pixel level VAL_1 can be smaller than the second pixel level VAL_2.

[0094] Furthermore, the pixel analysis circuit 240-1 can determine the final magnitude of the dimming value for reducing power consumption based on the pixel level at the point where the threshold value Th intersects the corresponding curve. For example, the pixel analysis circuit 240-1 can determine a larger decrease in the dimming value when the pixel level decreases, and can determine a smaller decrease in the dimming value when the pixel level increases. Since the first pixel level VAL_1 is lower than the second pixel level VAL_2, the pixel analysis circuit 240-1 can determine a larger decrease in the dimming value for the first pixel level VAL_1, and can determine a smaller decrease in the dimming value for the second pixel level VAL_2.

[0095] Figure 4 is a diagram illustrating actual measurements of pixel brightness reduction in response to a reduction in dimming value according to an embodiment.

[0096] Figure 4Actual measurement results are shown, showing that the rate of change of the dimming value and the rate of change of the pixel brightness vary depending on the pixel level. The decrease in the dimming value according to the pixel level from 0 to 255 and the decrease in the pixel brightness according to the pixel level can be actually measured in two setting environments. Figure 4 Shown are: a first curve graph 410, which shows the ratio of the brightness change rate of a pixel according to the pixel level from 0 to 255 to the dimming value change rate in a first setting environment (setting 1); and a second curve graph 420, which shows the ratio of the brightness change rate of a pixel according to the pixel level from 0 to 255 to the dimming value change rate in a second setting environment (setting 2).

[0097] In the first setting environment where the pixel level is 128, if the initial brightness (off brightness) is 77.58, if the subsequent brightness (on brightness) is 39.09, and if the rate of change of the dimming value (duty cycle, %) is 45.75, the rate of change of brightness (brightness ratio, %) can be 50.38, and the ratio of the rate of change of brightness to the rate of change of the dimming value (ratio, %) can be 110.13.

[0098] On the other hand, in the second setting environment where the pixel level is 128, if the initial brightness (off brightness) is 77.58, if the subsequent brightness (on brightness) is 56.06, and if the rate of change of the dimming value (duty cycle, %) is 77.83, the rate of change of brightness (brightness ratio, %) can be 72.27, and the ratio of the rate of change of brightness to the rate of change of the dimming value (ratio, %) can be 92.85.

[0099] Referring to the first graph 410 and the second graph 420, it can be understood that the ratio (ratio, %) of the rate of change of brightness to the rate of change of the dimming value varies depending on the pixel level. In addition, the ratio (ratio, %) of the rate of change of brightness corresponding to the pixel level to the rate of change of the dimming value may vary depending on the setting environment.

[0100] Figure 5 is a diagram illustrating an example of calculating a compensation gain according to an embodiment.

[0101] Figure 5 An example is shown in which a gain compensation circuit of an image data processing device calculates a compensation gain by reflecting the fact that a ratio of a change rate of brightness relative to a change rate of a dimming value differs according to pixel levels.

[0102] The gain compensation circuit can be reflected by Figure 4The actual characteristics shown in the graph in FIG are used to configure several points (e.g., several points at the pixel level) and interpolate the points to calculate the compensation gain. That is, the gain compensation circuit can obtain the compensation gain at some pixel levels and interpolate the compensation gain at some pixel levels to calculate the compensation gain at the remaining pixel levels.

[0103] The gain compensation circuit may use a lookup table for all pixel levels in order to calculate the precise compensation gain.

[0104] Figure 6 is a flowchart illustrating a local dimming operation of an image data processing apparatus according to an embodiment.

[0105] refer to Figure 6 , the image data processing device may receive a video image including a plurality of regions (step S602 ), where the plurality of regions include a plurality of pixels.

[0106] The image data processing device may analyze the original image data on the video image and may calculate a representative brightness value of each region (step S604 ).

[0107] The image data processing device may calculate a dimming value for each area according to the representative brightness value to adjust the brightness of the backlight (step S606 ).

[0108] The image data processing device may filter the dimming values ​​(step S608 ). The image data processing device may increase the dimming values ​​so that the difference in the dimming values ​​is reduced by filtering.

[0109] The image data processing apparatus may analyze the brightness distribution of pixels in each region (step S610 ).

[0110] The image data processing device may adjust the dimming value and output the adjusted dimming value (step S612). The image data processing device may output a dimming control signal to the backlight driving device based on the adjusted dimming value. The image data processing device may reduce the dimming value of an area with a low brightness distribution to reduce the brightness of the backlight in the area.

[0111] The image data processing apparatus may calculate a gain (step S614 ). The image data processing apparatus may calculate the gain by reflecting the fact that the ratio of the rate of change of the brightness of the pixel to the rate of change of the dimming value differs according to the pixel level.

[0112] The image data processing apparatus may generate image data converted from the original image data using the calculated gain (step S616 ).

[0113] Figure 7is a diagram illustrating a configuration of a dimming processing device included in an image data processing device according to another embodiment.

[0114] refer to Figure 7 The dimming processing device 700 may include an image analysis circuit 710, a dimming value calculation circuit 720, a filtering circuit 730, a pixel analysis circuit 740-1, a signal analysis circuit 740-2, a dimming control circuit 750, and a dimming output circuit 760. Figure 1 The dimming processing device 700 as a part of the image data processing device 110 may generate dimming values ​​DMV and DMV' and may output a dimming control signal DMS' based on the dimming values ​​DMV and DMV'. Specifically, the dimming processing device 700 may include components related to conversion of image data (e.g., Figure 2 The gain compensation circuit 270, Figure 2 The gain calculation circuit 280 and Figure 2 The remaining components except the data conversion circuit 290).

[0115] The image analysis circuit 710, the dimming value calculation circuit 720, the pixel analysis circuit 740-1, the signal analysis circuit 740-2, the dimming control circuit 750 and the dimming output circuit 760 can perform the same operation as described above. Figure 2 Therefore, in the following, only the additional functions will be described.

[0116] According to another embodiment, the filtering circuit 730 can perform filtering to prevent flickering that occurs when there is a large difference in dimming values ​​between one frame and the previous frame. The filtering circuit 730 can perform temporal filtering as described above and spatial filtering for changing the dimming value so that the difference between the dimming value in one area and the dimming value in an adjacent area is reduced.

[0117] The filter circuit 730 can receive a dimming value for determining the brightness of the backlight of the display device and can change the dimming value according to a function for determining the change characteristics of the dimming value when the frame changes. The filter circuit 730 can selectively use two or more functions with different dimming value change characteristics according to the change interval of the dimming value. Therefore, the filter circuit 730 can control the rate of change of the dimming value. Specifically, the filter circuit 730 can quickly change the dimming value in one interval and slowly change the dimming value in another interval.

[0118] For example, the filtering circuit 730 may receive an initial dimming value DMV from the dimming value calculation circuit 720. The filtering circuit 730 may perform temporal filtering on the initial dimming value DMV to generate a filtered dimming value DMV′. Here, compared to the initial dimming value DMV, the filtered dimming value DMV′ may be adjusted in terms of the rate of change between frames. Therefore, in the case of the initial dimming value DMV, the dimming value may be changed between frames according to a single function. On the other hand, in the case of the filtered dimming value DMV′, the dimming value may be changed between frames according to multiple functions. In the filtered dimming value DMV′, the dimming value may change faster in one interval than in other intervals. The filtering circuit 730 may transmit the filtered dimming value DMV′ to the dimming control circuit 750.

[0119] The dimming control circuit 750 may determine a final dimming value. The dimming control circuit 750 may calculate an adjusted dimming value DMV” from the filtered dimming value DMV’ by applying the analysis results of the brightness distribution of the pixel and the analysis results of the input dimming control signal DMS to the filtered dimming value DMV’. The dimming control circuit 750 may send the adjusted dimming value DMV” to the dimming output circuit 760.

[0120] The dimming output circuit 760 can convert the dimming value into a dimming control signal and output the dimming control signal to the backlight driving device. The dimming output circuit 760 can convert the adjusted dimming value DMV" into an adjusted dimming control signal DMS' and output the adjusted dimming control signal to the backlight driving device.

[0121] In addition, the dimming output circuit 760 can output a dimming control signal DMS' to the backlight driving device, adjusting the dimming control signal by reflecting the dimming value that changes for each frame. For example, if the dimming value changes from a first dimming value of a first frame to a second dimming value of a second frame after the first frame, the second dimming value can be applied to the dimming value DMV' filtered by the filtering circuit 730. An adjusted dimming value DMV" can be generated from the filtered dimming value DMV', and the adjusted dimming value DMV" can be converted into an adjusted dimming control signal DMS'. Therefore, the dimming output circuit 760 can output the adjusted dimming control signal DMS' reflecting the second dimming value to the backlight driving device.

[0122] Figure 8 is a diagram illustrating a detailed configuration of a filter circuit included in a dimming processing device according to another embodiment.

[0123] refer to Figure 8 The filtering circuit 730 may also include a dimming value receiving circuit 731 , a function providing circuit 732 and a dimming value adjusting circuit 733 .

[0124] The dimming value receiving circuit 731 may receive a dimming value (e.g., an initial dimming value DMV) and may transmit the dimming value to the dimming value adjusting circuit 733. Furthermore, the dimming value receiving circuit 731 may receive a dimming value in each frame. For example, if the dimming value changes from a first dimming value in a first frame to a second dimming value in a second frame after the first frame, the dimming value receiving circuit 731 may receive the first dimming value and the second dimming value from the dimming value calculating circuit 720.

[0125] The function providing circuit 732 may provide a function for determining the change characteristics of the dimming value to the dimming value adjustment circuit 733. Specifically, the function providing circuit 732 may provide multiple functions having different change characteristics of the dimming value. These functions may be used for modeling, wherein the dimming value adjustment circuit 733 changes the dimming value in the modeling.

[0126] Here, the function may define a rate of change or ratio of the dimming value. When the dimming value changes according to a frame change, the dimming value may change at the rate or ratio defined by the function. Multiple functions may define different rates or ratios depending on the inherent characteristics of the change in the dimming value. The dimming value may change at a rate defined by one function during one time period and at a rate defined by another function during another time period.

[0127] The dimming value adjustment circuit 733 can change the dimming value. The dimming value adjustment circuit 733 can receive multiple functions from the function providing circuit 732 and can change the dimming value according to the characteristics of the multiple functions. Specifically, the dimming value can change from a first dimming value to a second dimming value within the dimming time. The dimming value adjustment circuit 733 can change the dimming value according to a first function having a first characteristic in a first interval of the dimming time, and can change the dimming value according to a second function having a second characteristic different from the first characteristic in a second interval of the dimming time. It will be understood that the first dimming value is intended for the first frame, and the second dimming value is intended for the second frame after the first frame.

[0128] Accordingly, when the frame changes, the dimming value adjustment circuit 733 can change the dimming value from the first dimming value at a first rate defined by a first function in one interval of the dimming time (e.g., the first part of the dimming time), and can change the dimming value to the second dimming value at a second rate defined by a second function in another interval of the dimming time (e.g., the second part of the dimming time). Here, the first rate can be higher than the second rate, but the present disclosure is not limited thereto, and in some cases, the first rate can be lower than the second rate.

[0129] Figure 9is a diagram for explaining a change in the duty ratio of a PWM signal between frames according to another embodiment.

[0130] The PWM signal used as the dimming control signal can change in each frame. The PWM signal can be sent from the dimming processing device to the backlight driving device to adjust the brightness of the backlight. The brightness of the backlight can be changed according to the characteristics of the PWM signal (for example, frequency or duty cycle).

[0131] refer to Figure 9 If the frequency of the PWM signal is low, or if its duty cycle is short, the brightness of the backlight can be reduced. If the frequency of the PWM signal is high, or if the duty cycle of the PWM signal is long, the brightness of the backlight can be increased.

[0132] For example, the PWM signal may have a first duty cycle DT1 in the first frame FRAME1. The PWM signal may have a second duty cycle DT2 in the second frame FRAME2 following the first frame FRAME1. The second duty cycle DT2 may be longer than the first duty cycle DT1, which may indicate that the frequency of the PWM signal in the second frame FRAME2 is lower than the frequency of the PWM signal in the first frame FRAME1. When the PWM signal has the second duty cycle DT2, the backlight unit may be driven longer than when the PWM signal has the first duty cycle DT1. Therefore, the backlight may be brighter in the second frame FRAME2 than in the first frame FRAME1.

[0133] As shown in the figure, when the duty cycle of the PWM signal changes from a first duty cycle DT1 to a second duty cycle DT2, a dimming processing device according to another embodiment can adjust the rate of change to be high or low. Here, the dimming processing device can use multiple functions that can define different rate characteristics to adjust the rate of change. Changing the duty cycle of the PWM signal by the dimming processing device can be referred to as "modeling."

[0134] Figure 10 : is a diagram showing an example for explaining a change in a dimming value between frames.

[0135] refer to Figure 10 , the dimming value adjustment circuit of the traditional dimming processing device can use a function to model the change of the dimming value. Figure 10 In FIG. 5 , the change of the dimming value between frames can be represented as a graph of time TIME and dimming value VALUE.

[0136] If the dimming value adjustment circuit of the dimming processing device uses one function to change the dimming value, the dimming value may be changed from the initial dimming value to the target dimming value according to the one function.

[0137] For example, if the dimming value adjustment circuit of the dimming processing device changes the dimming value using a single function 1010, the dimming value may change from a first dimming value DMV1 to a second dimming value DMV2 along a curve indicated by the single function 1010. The dimming value may start changing from the first dimming value DMV1 at a start time Ts and may reach the second dimming value DMV2 at an end time Te.

[0138] Here, since the single function 1010 has nonlinear characteristics, the slope may change over time due to the nonlinear characteristics. The slope can be understood as the rate of change of the dimming value. Figure 10 In FIG. 1 , the slope of the single function 1010 may be steep at the beginning and may gradually become flatter later.

[0139] In addition, the time period in which the dimming value changes according to the change of the frame can be defined as "dimming time DmT". The dimming time DmT may include an initial interval DmTs close to the start time Ts and an end interval DmTe close to the end time Te. The dimming time DmT may also include an interval between the initial interval DmTs and the end interval DmTe. Since the dimming time DmT corresponds to the time period in which the dimming value changes from the dimming value of the current frame to the dimming value of the next frame, the dimming time DmT may occupy an interval of the next frame. Figure 10 In the embodiment, the dimming time DmT may occupy an interval of the second frame FRAME2 after the first frame FRAME1. The dimming value may completely change from the first dimming value DMV1 to the second dimming value DMV2 during the dimming time DmT and may be maintained at the second dimming value DMV2 after the dimming time DmT.

[0140] As described above, according to conventional dimming processing devices, the dimming value may fluctuate drastically because the rate of change of the dimming value is not regulated. Therefore, a sudden change in the dimming value may cause unnatural changes in frames and may cause flicker in the display for viewers.

[0141] Figure 11 : is a diagram showing a first example for explaining a change in a dimming value between frames according to another embodiment.

[0142] refer to Figure 11 According to another embodiment, the dimming value adjustment circuit of the dimming processing device can use multiple functions to model the change of the dimming value. Figure 11 In FIG. 5 , the change of the dimming value between frames can be represented as a graph of time TIME and dimming value VALUE.

[0143] If the dimming value adjustment circuit of the dimming processing device uses multiple functions to change the dimming value, the dimming value can be changed from the initial dimming value to the target dimming value according to the multiple functions. Here, the dimming value can be changed according to one of the multiple functions in one interval, and can be changed according to another of the multiple functions in another interval after the one interval.

[0144] For example, the dimming value may be maintained at the first dimming value DMV1 in the first frame FRAME1. When the frame changes from the first frame FRAME1 to the second frame FRAME2, the dimming value may change along the first function 1110 starting at the start time Ts of the start of the second frame FRAME2. The dimming value may change from the first dimming value DMV1 to the intermediate dimming value DMV_M. The intermediate dimming value DMV_M may be understood as a dimming value between the start dimming value and the target dimming value. Thereafter, the dimming value adjustment circuit of the dimming processing device may change the dimming value according to the second function 1120. Here, the dimming value may change according to the first function 1110 during the first interval S1 of the dimming time DmT, and the first interval S1 may include a portion or all of the initial interval DmTs in the dimming time DmT. In Figure 11 In the first step, the dimming value may be changed from the first dimming value DMV1 to the intermediate dimming value DMV_M according to the first function 1110 which is a nonlinear function during the first interval S1. Figure 11 The first step STEP1 or the first interval S1 may correspond to a portion where the dimming value changes from the first dimming value DMV1 to the middle dimming value DMV_M.

[0145] The first function 1110 can be either a nonlinear function or a linear function, but it is desirable that the first function 1110 be a nonlinear function in the first step, i.e., in the first interval S1 where the dimming value begins to change. A second-order polynomial function can correspond to a nonlinear function, and a first-order polynomial function can correspond to a linear function. Since a nonlinear function has a slope that varies over time, while a linear function has a slope that is constant over time, the rate of change of the dimming value according to a nonlinear function may suddenly increase, while the rate of change of the dimming value according to a linear function may be constant. Therefore, the rate of change of the dimming value according to a nonlinear function may generally be higher than the rate of change of the dimming value according to a linear function. If the change of the dimming value follows a nonlinear function during the end interval DmTe of the dimming time DmT, the dimming value may change abruptly, causing flicker in the display for the viewer. This also makes it difficult for the dimming value adjustment circuit to accurately adjust the suddenly changing dimming value. Therefore, the change of the dimming value needs to follow a nonlinear function at the beginning, i.e., during the initial interval DmTs of the dimming time DmT.

[0146] In the second step STEP2 or the second interval S2, the dimming value may be changed from the middle dimming value DMV_M to the second dimming value DMV2. The dimming value adjustment circuit of the dimming processing device may change the dimming value according to the second function 1120. Here, the dimming value may be changed according to the second function 1120 during the second interval S2 of the dimming time DmT, and the second interval S2 may include a portion or all of the end interval DmTe of the dimming time DmT. Figure 11 In the second step, the dimming value may be changed from the middle dimming value DMV_M to the second dimming value DMV2 according to the second function 1120 which is a linear function during the second interval S2. Figure 11 The second step STEP2 or the second interval S2 may correspond to a portion where the dimming value changes from the middle dimming value DMV_M to the second dimming value DMV2.

[0147] In addition, the first interval S1 can be longer or shorter than the second interval S2. The lengths of the first interval S1 and the second interval S2 can be different depending on the type of function used by the dimming value adjustment circuit, and generally, the interval using a nonlinear function can be shorter. This is due to the fact that when the dimming value changes according to a nonlinear function, the rate of change is high, and therefore the dimming value can quickly reach the target dimming value (e.g., the intermediate dimming value DMV_M). The dimming value can reach the final target dimming value according to another function (e.g., a linear function) after the target dimming value. Figure 11 As shown, the dimming value may change according to a first function 1110 in a first interval S1, and may change according to a second function 1120 in a second interval S2. In this case, the dimming value changes suddenly at the beginning and then changes smoothly later, thereby reducing the occurrence of flicker caused by the sudden change of the dimming value.

[0148] As described above, according to another embodiment of the dimming processing device, the change rate of the dimming value can be adjusted to prevent the dimming value from changing suddenly. Therefore, the smooth and flexible change of the dimming value can bring about a natural change of the frame and prevent flickering in the display for the viewer.

[0149] Figure 12 : is a diagram showing a second example for explaining a change in a dimming value between frames according to another embodiment.

[0150] refer to Figure 12 , the dimming value adjustment circuit of the dimming processing device according to another embodiment can adjust the time of changing from one function to another function while modeling the change of the dimming value using multiple functions.

[0151] First, the dimming value adjustment circuit of the dimming processing device can change the dimming value to a predetermined dimming value according to a function within a range. Second, the dimming value adjustment circuit can change the dimming value to a final target dimming value according to another function within another range. When the dimming value reaches the predetermined dimming value, the dimming value adjustment circuit can change the function used to change the dimming value to a function with different characteristics.

[0152] Typically, the predetermined dimming value may be a middle dimming value DMV_M (see Figure 11 ). However, the present disclosure is not limited thereto, and the predetermined dimming value may be smaller than the middle dimming value DMV_M.

[0153] For example, during the first interval S1, the dimming value adjustment circuit may change the dimming value from the first dimming value DMV1 at the start time Ts to a dimming value DMV_MS that is smaller than the middle dimming value DMV_M. Figure 12 In the first step, the dimming value may be changed from the first dimming value DMV1 to the dimming value DMV_MS smaller than the intermediate dimming value DMV_M according to the first function 1210 which is a nonlinear function during the first interval S1. Figure 12 The first step STEP1 or the first interval S1 may correspond to a portion where the dimming value changes from the first dimming value DMV1 to a dimming value DMV_MS that is smaller than the middle dimming value DMV_M.

[0154] In the second step STEP2 or the second interval S2, the dimming value may be changed from the dimming value DMV_MS which is less than the middle dimming value DMV_M to the second dimming value DMV2. The dimming value adjustment circuit of the dimming processing device may change the dimming value according to the second function 1220. Figure 12 In the second step, the dimming value may be changed from a dimming value DMV_MS smaller than the middle dimming value DMV_M to a second dimming value DMV2 as a target dimming value according to a second function 1220 as a linear function during the second interval S2. Figure 12 The second step STEP2 or the second interval S2 may correspond to a portion where the dimming value changes from a dimming value DMV_MS smaller than the middle dimming value DMV_M to a second dimming value DMV2.

[0155] Figure 13 : is a diagram showing a third example for explaining a change in a dimming value between frames according to another embodiment.

[0156] refer to Figure 13 , the dimming value adjustment circuit of the dimming processing device according to another embodiment can adjust the time of changing from one function to another function while modeling the change of the dimming value using multiple functions.

[0157] Typically, the predetermined dimming value may be a middle dimming value DMV_M (see Figure 11 ). However, the present disclosure is not limited thereto, and the predetermined dimming value may be greater than the middle dimming value DMV_M.

[0158] For example, during the first interval S1, the dimming value adjustment circuit may change the dimming value from the first dimming value DMV1 at the start time Ts to a dimming value DMV_ML greater than the middle dimming value DMV_M. Figure 13 In the first step, the dimming value may be changed from a first dimming value DMV1 to a dimming value DMV_ML greater than the middle dimming value DMV_M according to a first function 1310 as a nonlinear function during a first interval S1. Figure 13 The first step STEP1 or the first interval S1 may correspond to a portion where the dimming value changes from the first dimming value DMV1 to a dimming value DMV_ML greater than the middle dimming value DMV_M.

[0159] In the second step STEP2 or the second interval S2, the dimming value may be changed from the dimming value DMV_ML greater than the middle dimming value DMV_M to the second dimming value DMV2. The dimming value adjustment circuit of the dimming processing device may change the dimming value according to the second function 1320. Figure 13 In the second step, the dimming value may be changed from the dimming value DMV_ML greater than the intermediate dimming value DMV_M to the second dimming value DMV2 as the target dimming value according to the second function 1320 as a linear function during the second interval S2. Figure 13 The second step STEP2 or the second interval S2 may correspond to a portion where the dimming value changes from the dimming value DMV_ML greater than the middle dimming value DMV_M to the second dimming value DMV2.

[0160] CROSS-REFERENCE TO RELATED APPLICATIONS

[0161] This application claims priority from Korean Patent Application No. 10-2020-0048515, filed on April 22, 2020, which is hereby incorporated by reference in its entirety.

Claims

1. A dimming processing device for adjusting a dimming value of a backlight, the dimming processing device comprising: a dimming value receiving circuit configured to receive a first dimming value and a second dimming value, wherein the first dimming value and the second dimming value are used to adjust the backlight, and wherein a frame includes a first time interval, a second time interval after the first time interval, and a third time interval after the second time interval; and The dimming value adjustment circuit is configured as follows: adjusting the first dimming value to a predetermined dimming value at a first rate defined by a first function during the first time interval, During the second time interval, the predetermined dimming value is adjusted to the second dimming value at a second rate defined by a second function that is different from the first rate, and maintaining the second dimming value during the third time interval, The predetermined dimming value is a value between the first dimming value and the second dimming value.

2. The dimming processing device according to claim 1, wherein: The dimming value adjustment circuit is configured to adjust the dimming value from the first dimming value to the second dimming value when the frame changes between adjacent frames.

3. The dimming processing device according to claim 1, wherein: A rate of change of the dimming value according to the first function in the first time interval is higher than a rate of change of the dimming value according to the second function in the second time interval.

4. The dimming processing device according to claim 3, wherein: The first time interval is shorter than the second time interval.

5. The dimming processing device according to claim 4, wherein: The dimming value adjustment circuit is configured to adjust the dimming value to a third dimming value between the first dimming value and the second dimming value according to the first function. The dimming processing device according to claim 4 , wherein: The dimming value adjustment circuit changes the dimming value from a third dimming value between the first dimming value and the second dimming value according to the second function.

7. The dimming processing device according to claim 3, wherein: The first time interval includes at least a portion of an initial time interval of a dimming change time and the second time interval includes at least a portion of a subsequent time interval of the dimming change time.

8. The dimming processing device according to claim 3, wherein: The rate of change of the dimming value varies with time in the first time interval and is constant with time in the second time interval.

9. The dimming processing device according to claim 1, wherein: The dimming value adjustment circuit is configured to adjust the dimming value to a third dimming value between the first dimming value and the second dimming value according to the first function, and to change the dimming value from the third dimming value according to the second function.

10. The dimming processing device according to claim 1, wherein: The first function and the second function are functions of time, and the first function has a slope that decreases with time in the first time interval.

11. The dimming processing device according to claim 1, wherein: The first function is a non-linear function and the second function is a linear function.

12. The dimming processing device according to claim 1, wherein: The first function has a slope that varies with time and the second function has a slope that is constant with time.

13. A dimming processing device for adjusting a dimming value of a backlight, the dimming processing device comprising: a dimming value receiving circuit configured to receive a target dimming value; as well as a dimming value adjustment circuit configured to adjust the dimming value according to the target dimming value during a dimming change time interval in a frame, in, When the frame changes, the dimming value adjustment circuit is configured to: i) adjusting the dimming value to a predetermined dimming value at a first change rate defined by a first function during a first time interval of a first frame, ii) increasing the predetermined dimming value to the target dimming value at a second changing rate defined by a second function during a second time interval of the first frame, and iii) maintaining the target dimming value during a third time interval of the first frame, The second time interval is after the first time interval, The third time interval is after the second time interval, and The first rate of change and the second rate of change are different from each other, The predetermined dimming value is a value between the first dimming value and the second dimming value.

14. The dimming processing device according to claim 13, wherein: The first time interval has an interval different from that of the second time interval.

15. The dimming processing device according to claim 13, wherein: The dimming value receiving circuit is configured to receive a first target dimming value for determining the brightness of the backlight in a first frame and a second target dimming value for determining the brightness of the backlight in a second frame, and The dimming value adjustment circuit is configured to adjust the dimming value from the first target dimming value to a predetermined dimming value between the first target dimming value and the second target dimming value at a first change rate during an initial time interval.

16. The dimming processing device according to claim 15, wherein: The dimming value adjustment circuit is configured to adjust the dimming value from the predetermined dimming value to the second target dimming value at a second changing rate during a subsequent time interval.

17. A timing controller for outputting a dimming control signal for a backlight, the timing controller comprising: The dimming value adjustment circuit is configured as follows: i) changing the dimming value of the backlight from a first dimming value to a predetermined dimming value according to a first change rate of the dimming value defined by a first function during a first time interval within a frame, ii) changing the dimming value from the predetermined dimming value to a second dimming value according to a second rate of change of the dimming value defined by a second function during a second time interval within the frame, and iii) maintaining the second dimming value during a third time interval within the frame, in, The second time interval is after the first time interval, The third time interval is after the second time interval, and The first rate of change and the second rate of change are different from each other, The predetermined dimming value is a value between the first dimming value and the second dimming value.

18. The timing controller according to claim 17, wherein: The first dimming value and the second dimming value are generated according to a control signal received from a host.

19. The timing controller according to claim 17, wherein: The dimming output circuit is configured to send the dimming control signal to a backlight driving device for adjusting the brightness of the backlight.

20. The timing controller according to claim 17, wherein: A changing rate of the dimming value in the first time interval is higher than a changing rate of the dimming value in the second time interval.

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