TWI783567B - Drive device and control method for a display - Google Patents

Abstract

A driving device for a display includes an image processing circuit, a display driver, and a light driver. The image processing circuit compensating a first image data according to a brightness data to generate a compensation image data. The display driver controls a display panel of the display to show an image according to the compensation image data between a first time point and a second time point. The light source driver updates a brightness of a backlight plate of the display based on the brightness data at a third point between the first time point and the second time point.

Description

Display drive device and control method

The invention relates to a display, in particular to a method for adjusting the brightness of the backlight panel of the display.

A traditional liquid crystal display includes a display panel and a backlight. The control of the display panel and the backlight needs to be coordinated to improve image quality. Therefore, the timing control of the display panel and the backlight has become a very important issue.

The object of the present invention is to provide a display driving device and a control method.

According to the present invention, a display driving device includes an image processing circuit, a display driver and a light source driver. The image processing circuit compensates a first image data according to a brightness data to generate a compensated image data. The display driver controls the display panel of the display to display an image between a first time point and a second time point according to the compensated image data. The light source driver updates the brightness of the backlight panel of the display according to the brightness data at a third time point between the first time point and the second time point.

According to the present invention, a method for controlling a display includes the following steps: compensating a first image data according to a luminance data to obtain a compensated image data; controlling the display panel of the display according to the compensated image data at a first time point and An image is displayed between a second time point; and at a third time point between the first time point and the second time point, the brightness of the backlight panel of the display is updated according to the brightness data.

The invention can improve the image quality and further improve the visual effect.

In a liquid crystal display with a local dimming system, the image data needs to be compensated according to the brightness data of the backlight. FIG. 1 provides a schematic diagram of a multi-frame continuous image, which includes image data of the M-2-M+1th frame (frame). FIG. 2 and FIG. 3 respectively show two updating sequences of the display panel and the backlight panel in the liquid crystal display. As shown in FIG. 2 and FIG. 3 , the display panel has n scanning lines L ₁ -L _n (not shown in the figure) which are sequentially updated according to the compensated image data a - c and a' - c'. Scan line L1 is updated at time _t1 , scan line _{Ln/4 is} updated at time tn _/4 , scan line _Ln/2 is updated at time tn _/2 , scan line _Ln is updated at time _tn . The backlight panel has a plurality of light emitting elements (such as light emitting diodes). The backlight board controls the brightness of the plurality of light-emitting elements according to a brightness data. The brightness data of the backlight is determined according to the image data and used to compensate the image data. In FIG. 2 and FIG. 3 , the brightness data A of the backlight panel is determined according to the image data of frame M-2 in FIG. 1 . The brightness data B of the backlight is determined according to the image data of frame M-1 in FIG. 1 . The brightness data C of the backlight is determined according to the image data of frame M in FIG. 1 .

Because the display panel updates the image data of the scanning lines L ₁ ~L _n one by one, while the backlight panel updates the brightness of all its light-emitting elements at the same time, so there is a mismatch between the two. In the example shown in Figure 2, the compensated image data a of the M-1th frame is obtained by compensating the M-1th frame image based on the brightness data B of the next frame, and the compensated image data b of the M-th frame is obtained according to the next frame The luminance data C of the frame is obtained by compensating the image of the Mth frame. During the process of displaying the compensated image data a of frame M− ₁ on the display, the updated data of the scanning line L1 at time t1a will last for _one frame, and will not be updated again until time _t1b . Since the compensated image data A of the M−1 frame is obtained by compensating the M−1 frame image according to the luminance data B, the luminance data matched by the updated data of the scanning line L1 at time t ₁ a is B. However, since the time point when the backlight updates the luminance according to the luminance data B is one frame later than the time point when the display starts to display the image data a, the updated data of the scan line L1 at time t _{1 a} is only equal to the luminance of the backlight board Matches are only made during period CP ₁ . Similarly, the updated data of scanning line L _n/4 at time t _n/4 a matches the brightness of the backlight panel only in period CP ₂ , and the updated data of scanning line L _n/2 at time t _n/2 a matches the brightness of the backlight panel. The brightness of the panel matches only during the period CP ₃ , and the updated data of the scanning line L _n at time t _n a matches the brightness of the backlight panel only during the period CP _n .

In the example shown in Figure 3, the compensated image data a' of the M-1th frame is obtained by compensating the M-1th frame image based on the luminance data A of the same frame, and the compensated image data b' of the M-th frame is obtained based on the same The brightness data B of the frame is obtained by compensating the image of the Mth frame. During the process of displaying the compensated image data b' of the Mth frame on the display, the updated data of the scan line L ₁ at time t ₁ b will last for one frame, and will not be updated again until time t ₁ c. Since the compensated image data a of the Mth frame is obtained by compensating the M- _1th frame image according to the brightness data B, the brightness data matched by the updated data of the scanning line L1 at time _t1b is B. However, since the scanning lines L ₁ -L _n are updated sequentially, and the time points are different from the time points when the backlight panel updates the luminance according to the luminance data B. Therefore, the updated data _of the scan line L1 at the time _t1b matches the brightness _of the backlight panel only during the time period CP1. Similarly, the data updated by scanning line L _n/4 at time t _n/4 b matches the brightness of the backlight panel only in period CP ₂ , and the data updated by scanning line L _n/2 at time t _n/2 b matches the brightness of the backlight panel. The brightness of the panel matches only during the period CP ₃ , and the updated data of the scanning line L _n at time t _n b matches the brightness of the backlight panel only during the period CP _n .

FIG. 4 shows the driving device 20 for driving the display 10 of the present invention. FIG. 5 is an embodiment of the display 10 in FIG. 4 . Referring to FIGS. 4 and 5 , the display 10 includes a display panel 12 and a backlight 14 . The display panel 12 includes a plurality of display areas 122 , and each display area 122 includes a plurality of pixels (not shown in the figure) for displaying images. The backlight 14 is located below the display panel 12 and has a plurality of light-emitting regions 142, the plurality of light-emitting regions 142 correspond to the plurality of display regions 122, and each light-emitting region 142 includes a plurality of light-emitting elements (not shown), such as light emitting diode. Referring to FIG. 4 , the driving device 20 includes an image processing circuit 22 , a display driver 24 and a light source driver 26 . The image processing circuit 22 sequentially receives the image data P1 and the image data P2, wherein the image data P1 and the image data P2 are images representing two consecutive frames. After receiving the image data P1, the image processing circuit 22 determines a brightness data B according to the image data P1. Then, when the image processing circuit 22 receives the image data P2, the image processing circuit 22 compensates the image data P2 according to the brightness data B to generate a compensated image data Pc. In addition to outputting the compensated image data Pc and brightness data B to the display driver 24 and the light source driver 26 respectively, the image processing circuit 22 also provides a vertical synchronization signal Vsync and a brightness update signal S to the display driver 24 and the light source driver 26 respectively. Light source driver 26.

FIG. 6 shows the update sequence of the display panel 12 and the backlight 14 in FIG. 4 . Based on brevity, the embodiment of FIG. 6 only takes two consecutive frames of images as an example for illustration, but the present invention is not limited thereto. Those familiar with the technical field should be able to understand FIG. 6 and apply it to continuous multiple frames of images . Referring to FIG. 4 and FIG. 6 , in FIG. 6 , the vertical synchronization signal Vsync1 is at the time point T1 , the vertical synchronization signal Vysnc2 is at the time point T2 , and the vertical synchronization signal Vsync3 is at the time point T3 . A display period is between two adjacent vertical synchronous signals Vsync. During the display period from time point T1 to T2 , the display driver 24 controls the display panel 12 to display an image according to the compensated image data Pc from the image processing circuit 22 . As mentioned above, the compensated image data Pc is generated by compensating the image data P2 according to the brightness data B, and the brightness data B is calculated according to the image data P1. The display driver 24 sequentially updates the data of the plurality of scan lines L ₁ -L _n of the display panel 12 between the time points t ₁ a and t _na in response to the vertical synchronization signal Vsync1 at the time point T1 . The first scan line L ₁ is updated at time t ₁ a, scan line L _n/4 is updated at time t _n/4 a, scan line L _n/2 is updated at time t _n/2 a, and the last scan line L _n is updated at time t _n a. There is a time difference Δt1 between the time point T1 of the vertical synchronization signal Vsync1 and the time point t ₁ a of updating the first scanning line L ₁ , and the time point t _n a of updating the last scanning line L _n is the same as the vertical synchronization signal There is a time difference Δt2 between the time points T2 where Vsync2 is located. Since the difference Δt1 and Δt2 are very small, they are practically negligible.

One of the characteristics of the control method shown in FIG. 6 is that the light source driver 26 is at the time point T4 between the time point T1 and the time point T2 (or more precisely, between the time points t ₁ a and t _na ). , update the brightness of the backlight panel 14 according to the brightness data B. Specifically, the light source driver 26 updates the brightness of the backlight panel 14 according to the brightness data B at the time point T4 in response to the brightness update signal S received. The luminance data B includes a plurality of area data (not shown in the figure) respectively corresponding to a plurality of light emitting areas 142 of the backlight panel 14 . In one embodiment, each light emitting area 142 includes one or more light emitting elements (such as light emitting diodes). The light source driver 26 separately controls the brightness of all the light emitting elements in each light emitting region 142 according to a plurality of region data. In one embodiment, the time point T4 is in the middle of the time point T1 and the time point T2. In another embodiment, the time point T4 is the time point t _n/2 a, that is, the time point t ₁ a for updating the first scan line L ₁ and the time point t _n for updating the last scan line L _n the middle of a.

Compared with the control method in FIG. 2 , the control method in FIG. 6 can be understood as delaying the update time of the backlight panel 14 , so that the time point T4 for updating the brightness of the backlight panel 14 is later than the time point T1 . Or, more precisely, the time point T4 for updating the brightness of the backlight panel 14 is later than the time point t ₁ a for updating the first scan line L1.

According to the timing sequence in FIG. 6 , the updated data of scanning line L1 at time _t1a matches the brightness of backlight panel 14 at period CP1, and the updated data of scanning line _{Ln/4 at} time tn _{/ 4a} matches the brightness of backlight panel 14 The brightness of the scan line _Ln/2 is matched at the period CP _n/4 , and the data updated at the time t _n/2 a is matched with the brightness of the backlight panel 14 at the period CP _n/2 , and the scan line _Ln is updated at the time t _n a The data of is matched with the brightness of the backlight panel 14 in the period CP _n .

In FIG. 2 and FIG. 3 , the difference between the time intervals CP ₁ and CP _n is too large, which may lead to obvious differences in color or brightness between the upper and lower sides of the display panel, resulting in poor visual effects. Compared with the timing diagram in FIG. 2 or FIG. 3 , the periods CP ₁ -CP _n in FIG. 6 are relatively uniform, and the difference between the maximum value and the minimum value in the period CP ₁ -CP _n is significantly smaller. Therefore, the control method in FIG. 6 can obtain a better visual effect.

The image processing circuit 22 includes a timing controller (Timing controller) 222 . As shown in FIG. 7, the timing controller 222 in the image processing circuit 22 is used to receive the image data P1 and the image data P2, and output the compensated image data Pc and the vertical synchronization signal Vsync to the display driver 24, and output the brightness data B and brightness The update signal S is sent to the light source driver 26 . The display driver 24 controls the display panel 12 to display images in response to the vertical synchronization signal Vsync. The light source driver 26 updates the brightness of the backlight panel 14 at time point T4 in response to the brightness update signal S. The timing controller 222 includes a delay circuit 2222 and a local dimming processor 2224 . The delay circuit 222 is used to delay the vertical synchronization signal Vsync to generate the brightness update signal S, so that the brightness update signal S is output after a period of time after the vertical synchronization signal Vsync is output. The local dimming processor 2224 sequentially receives the image data P1 and the image data P2. The local dimming processor 2224 processes the received image data P1 to generate brightness data B, and then uses the brightness data B to compensate the image data P2 to generate compensated image data Pc.

Please refer to Figure 8. In another embodiment, the image processing circuit 22 includes a bridge chip 224 and a timing controller 226 . The bridge chip 224 sequentially receives the image data P1 and the image data P2 , and outputs the brightness data B and the brightness update signal S to the light source driver 26 , and outputs the compensated image data Pc to the timing controller 226 . The bridge chip 224 includes a delay circuit 2242 and a local dimming processor 2244 . The delay circuit 2242 receives the vertical synchronous signal Vsync from the timing controller 226, and delays the vertical synchronous signal Vsync to generate the brightness update signal S, so that the brightness update signal S is output after a period of time after the vertical synchronous signal Vsync is output. The local dimming processor 2244 receives the image data P1 and the image data P2 in sequence. The local dimming processor 2244 processes the received image data P1 to generate brightness data B, and then uses the brightness data B to compensate the image data P2 to generate compensated image data Pc. The timing controller 226 receives the compensated image data Pc from the local dimming processor 2244 , and outputs the compensated image data Pc and the vertical synchronization signal Vsync to the display driver 24 . The display driver 24 controls the display panel 12 to display images in response to the vertical synchronization signal Vsync.

FIG. 9 shows an embodiment of the light source driver 26 . The light source driver 26 in FIG. 9 includes a first selector 261 , a second selector 262 , a first register 263 , a second register 264 , a driving unit 265 and a timing controller 266 . The first selector 261 is connected to the image processing circuit 22 , the first register 263 and the second register 264 . The first selector 261 sequentially stores the first part of the brightness data B in the first register 263 and stores the second part of the brightness data B in the second register 264 according to a selection signal Se1. The second selector 262 is connected to the first register 263 and the second register 264, and determines to output the first part or the second part according to the selection signal Se1. The drive unit 265 is connected to the second selector 263, updates the brightness of the first area of the backlight panel 14 according to the first part output by the second selector 262, and updates the second part of the backlight panel 14 according to the second part output by the second selector 263. The brightness of the area. The timing controller 266 receives the brightness update signal S, and generates a selection signal Se1 in response to the brightness update signal S to control the first selector 261 and the second selector 262 to sequentially output the first part and the second part of the brightness data B.

It can be understood from the embodiment of FIG. 9 that the storage space of the first register 263 and the second register 264 is smaller than the data amount of the luminance data B. Referring to FIG. The advantage of this configuration is that it can save the register space in the light source driver 26, help to reduce the area of the light source driver 26, and save cost.

In the foregoing description, the brightness data B is determined according to the image data P1. In other embodiments, the brightness data B may also be determined in other ways, such as determined according to the image data P2. Therefore, the method provided by the invention can be understood as comprising the following steps: Compensating an image data according to a brightness data to obtain a compensated image data; controlling a display panel to display an image between a first time point and a second time point according to the compensated image data; and At a third time point between the first time point and the second time point, the brightness of a backlight panel is updated according to the brightness data.

The above description is only an embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with the embodiment, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field, Within the scope of not departing from the technical solution of the present invention, when the technical content disclosed above can be used to make some changes or be modified into equivalent embodiments with equivalent changes, but all the content that does not depart from the technical solution of the present invention, according to the technical essence of the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

10: Display 12: Display panel 122: display area 14: Backlight panel 142: Luminous area 20: Drive device 22: Image processing circuit 222: Timing controller 2222: delay circuit 2224: Local Dimming Processor 224: bridge chip 2242: delay circuit 2244: Local Dimming Processor 226: Timing controller 24:Display driver 26: Light source driver 261: First selector 262: Second selector 263: The first register 264: Second register 265: drive unit 266: Timing controller

FIG. 1 shows a schematic diagram of providing multiple frames of continuous images. FIG. 2 is a first embodiment of the update sequence of the display panel and the backlight panel. FIG. 3 is a second embodiment of the refresh sequence of the display panel and the backlight panel. Fig. 4 shows an embodiment of the driving device of the present invention. FIG. 5 shows an embodiment of the display in FIG. 4 . FIG. 6 shows an embodiment of refresh sequence of the display panel and the backlight panel in FIG. 4 . FIG. 7 shows a first embodiment of the image processing circuit in FIG. 4 . FIG. 8 shows a second embodiment of the image processing circuit in FIG. 4 . Figure 9 shows an embodiment of a light source driver.

10: Display

12: Display panel

14: Backlight panel

20: Drive device

22: Image processing circuit

24:Display driver

26: Light source driver

Claims (15)

A display driving device, the display includes a display panel and a backlight plate, the driving device includes: an image processing circuit, which performs the following operations: compensate a first image data according to a brightness data to generate a compensated image data; A display driver, connected to the image processing circuit, controls the display panel to display an image between a first time point and a second time point according to the compensated image data; and a light source driver, connected to the image processing circuit, in the At a third time point between the first time point and the second time point, the brightness of the backlight panel is updated according to the brightness data. The driving device according to claim 1, wherein the third time point is in the middle of the first time point and the second time point. The driving device according to claim 1, wherein the brightness data includes a plurality of area data respectively corresponding to a plurality of light-emitting areas of the backlight panel, and the light source driver respectively controls the brightness of each light-emitting area according to the plurality of area data. The driving device according to claim 1, wherein before compensating the first image data, the operation performed by the image processing circuit further includes: sequentially receiving a second image data and the first image data; and according to the first image data The image data or the second image data determine the brightness data. The driving device according to claim 4, wherein the image processing circuit includes a timing controller to receive the first image data and the second image data, and output the brightness data and the compensation image data. The driving device as claimed in item 5, wherein the timing controller generates a vertical synchronization signal and a brightness update signal to the display driver and the light source driver respectively, wherein the display driver controls the display panel to display the image in response to the vertical synchronization signal, and the light source driver updates the backlight panel at the third time point in response to the brightness update signal brightness. The driving device as claimed in claim 6, wherein the timing controller includes: a delay circuit connected to the light source driver for delaying the vertical synchronization signal to generate the brightness update signal, so that the brightness update signal passes through the output of the vertical synchronization signal output after a period of time; a local dimming processor, connected to the display driver and the light source driver, processes the second image data to generate the brightness data, and uses the brightness data to compensate the first image data to generate the compensation video material. The driving device as in claim 4, wherein the image processing circuit includes: a bridge chip, receiving the first image data and the second image data, and outputting the brightness data and the compensation image data; and a timing controller connected to The bridge chip and the display driver receive the compensation image data from the bridge chip and transmit the compensation image data to the display driver. The driving device according to claim 8, wherein the timing controller generates a vertical synchronization signal to the display driver, and the display driver controls the display panel to display the image in response to the vertical synchronization signal. The driving device according to claim 9, wherein the bridge chip receives the vertical synchronous signal, and generates a brightness update signal to output to the light source driver accordingly, and the bridge chip includes: a delay circuit connected to the timing controller for delay The vertical synchronization signal is used to generate the brightness update signal, so that the brightness update signal is output after a period of time after the vertical synchronization signal is output; and a local dimming processor, connected to the timing controller, processes the second image data to generate The brightness data, and using the brightness data to compensate the first image data to generate the compensation image data. The driving device according to claim 1, wherein the light source driver includes: a first register; a second register; a first selector connected to the image processing circuit, the first register and the second a temporary register, which sequentially stores the first part of the luminance data in the first temporary register and stores the second part of the luminance data in the second temporary register according to a selection signal; a second selector connected to The first temporary register and the second temporary register determine to output the first part or the second part according to the selection signal; and a drive unit is connected to the second selector, and according to the The first part updates the brightness of the first area of the backlight board, and updates the brightness of the second area of the backlight board according to the second part output by the second selector. A method for controlling a display, the display comprising a display panel and a backlight panel, the control method comprising the following steps: compensating a first image data according to a brightness data to obtain a compensated image data; controlling the display according to the compensated image data The panel displays an image between a first time point and a second time point; and at a third time point between the first time point and the second time point, starting to update the backlight panel according to the brightness data brightness. The control method according to claim 12, wherein the third time point is located in the middle of the first time point and the second time point. The control method according to claim 12, wherein the backlight panel includes a plurality of light-emitting areas, each area includes a plurality of light-emitting elements, and the brightness data includes a plurality of area data respectively corresponding to the A plurality of light-emitting areas, the step of controlling the backlight includes controlling the brightness of the plurality of light-emitting elements in each of the light-emitting areas respectively according to the data of each of the areas. The control method according to claim 12, wherein before the step of compensating the first image data, the control method further includes: sequentially receiving a second image data and the first image data; and according to the first image data Or the second image data determines the brightness data.

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