Backlight device, method of operation, and display device for improving dynamic blur

Abstract

The present application provides a backlight device, an operating method and a display device for improving dynamic blur. The display device includes a display panel, a scaler integrated circuit and a backlight device. The backlight device includes N light zones for providing backlight to the display panel, where N is a positive integer. The backlight device lights each of the N light zones in a time-division manner in each of a plurality of scanning periods. A time length of each of the scanning periods is greater than or equal to a time length of a video active period of the display panel. A continuous lighting time length of each of the N light zones is less than or equal to a quotient of the time length of the video active period divided by N.

Description

Technical Field

[0001] This invention relates to the field of backlight displays, and particularly to a backlight device, operating method, and display device for improving motion blur. Background Technology

[0002] Liquid crystal displays (LCDs) are common hold-type displays. That is, for each pixel, the pixel value is maintained until it is updated in the next video frame. Due to this hold-type characteristic, moving objects in the image appear static (not moving) until a new frame is updated. Users expect the position of objects in the image based on their speed of movement, but the hold-type characteristic of LCDs causes motion blur in human vision. Motion blur degrades image quality and can cause viewing discomfort. Improving motion blur is one of the many technical challenges in this field. Summary of the Invention

[0003] The present invention provides a backlight device, an operating method, and a display device to improve motion blur.

[0004] To achieve the above objectives, the present invention provides a backlight device comprising:

[0005] The backlight module includes N light zones for providing backlight to the display panel, where N is a positive integer; and

[0006] A local dimming circuit, coupled to the backlight module, is used to illuminate each of the N light zones in a time-division manner during each of a plurality of scan cycles; wherein the duration of each of the plurality of scan cycles is greater than or equal to the duration of the (Video Active Data) data of the display panel, and the duration of continuous illumination of each of the N light zones is less than or equal to the quotient of the duration of the video active data divided by N.

[0007] Ideally, the durations of the multiple scan cycles should be equal.

[0008] Preferably, the duration of each of the plurality of scan cycles is less than or equal to the duration of the display frame of the display panel.

[0009] Preferably, the multiple scan cycles are asynchronous with the multiple display frames of the display panel.

[0010] Preferably, the dimming circuit performs regional dimming calculations to dynamically adjust the brightness of each of the N light zones; or, the dimming circuit performs black insertion calculations to dynamically adjust the continuous illumination time of each of the N light zones.

[0011] To achieve the above objectives, the present invention also proposes a method for operating a backlight device, comprising:

[0012] The local dimming circuit of the backlight device illuminates each of the N light zones of the backlight module of the backlight device in a time-division manner in each of a plurality of scanning cycles to provide backlight to the display panel, where N is a positive integer;

[0013] The dimming circuit in that area adjusts the duration of the plurality of scan cycles so that the duration of each of the plurality of scan cycles is greater than or equal to the duration of the effective video data period of the display panel; and

[0014] The dimming circuit in that area adjusts the continuous illumination time of each of the N light zones so that the continuous illumination time of each of the N light zones is less than or equal to the quotient of the duration of the valid video data divided by N.

[0015] Ideally, the durations of the multiple scan cycles should be equal.

[0016] Preferably, the duration of each of the plurality of scan cycles is less than or equal to the duration of the display frame of the display panel.

[0017] Preferably, the multiple scan cycles are asynchronous with the multiple display frames of the display panel.

[0018] Preferably, it also includes: performing a dimming calculation in the region by the dimming circuit in that region to dynamically adjust the brightness of each of the N light zones.

[0019] Preferably, it also includes: performing a black-insertion calculation by the dimming circuit of the area to dynamically adjust the continuous illumination time of each of the N light zones.

[0020] To achieve the above objectives, the present invention also proposes a display device comprising: a display panel; a scaler integrated circuit (SIC) coupled to the display panel; and a backlight device coupled to the scaler integrated circuit, wherein the backlight device includes N light zones for providing backlight to the display panel, where N is a positive integer, and the backlight device illuminates each of the N light zones in a time-division multiplexing manner in each of a plurality of scan cycles, wherein the duration of each of the plurality of scan cycles is greater than or equal to the duration of the video data period of the display panel, and the continuous illumination duration of each of the N light zones is less than or equal to the quotient of the duration of the video data period divided by N.

[0021] Preferably, the backlight device includes: a backlight module including the N light zones for providing backlight to the display panel; and a local dimming circuit coupled to the backlight module for time-division multiplexing each of the N light zones in each of the plurality of scan cycles.

[0022] Ideally, the durations of the multiple scan cycles should be equal.

[0023] Preferably, the duration of each of the plurality of scan cycles is less than or equal to the duration of the display frame of the display panel.

[0024] Preferably, the multiple scan cycles are asynchronous with the multiple display frames of the display panel.

[0025] Preferably, the backlight device performs regional dimming calculations to dynamically adjust the brightness of each of the N light zones; or, the backlight device performs black insertion calculations to dynamically adjust the continuous illumination time of each of the N light zones.

[0026] Preferably, the scaler integrated circuit performs local dimming calculations to control the backlight device to dynamically adjust the brightness of each of the N light zones.

[0027] Preferably, the scaler integrated circuit performs black insertion calculations to control the backlight device to dynamically adjust the continuous illumination time of each of the N light zones.

[0028] Compared to existing technologies, the backlight device in the above embodiments disclosed in this invention provides backlight to the display panel by illuminating different light zones in a time-division manner. By utilizing the technique of zonal backlight illumination, the backlight device can reduce the image persistence characteristics of the display panel and improve the motion blur problem of the display panel. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a circuit block of a display device according to an embodiment of the present invention.

[0030] Figure 2 This is a schematic flowchart illustrating the operation method of a backlight device according to an embodiment of the present invention.

[0031] Figure 3 This is a circuit diagram of a local dimming circuit and a backlight module, drawn according to an embodiment of the present invention.

[0032] Figure 4 This is a driving timing diagram illustrating, according to an embodiment of the present invention, that all four light zones of the backlight module are illuminated in a time-division manner.

[0033] Figure 5This is a driving timing diagram illustrating, according to another embodiment of the present invention, that all four light zones of the backlight module are illuminated in a time-division manner.

[0034] Figure 6 This is a driving timing diagram illustrating, according to another embodiment of the present invention, that all four light zones of the backlight module are illuminated in a time-division manner.

[0035] Figure 7 This is a driving timing diagram illustrating, according to another embodiment of the present invention, that all four light zones of the backlight module are illuminated in a time-division manner. Detailed Implementation

[0036] To provide a further understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0037] The term "coupled (or connected)" as used throughout this specification (including the claims) may refer to any direct or indirect means of connection. For example, if the text describes a first device coupled (or connected) to a second device, it should be interpreted as the first device being directly connected to the second device, or the first device being indirectly connected to the second device through other devices or some means of connection. The terms "first," "second," etc., used throughout this specification (including the claims) are used to name elements or distinguish different embodiments or scopes, and are not intended to limit the upper or lower limit of the number of elements, nor to limit the order of elements. Furthermore, wherever possible, elements / components / steps using the same reference numerals in the drawings and embodiments represent the same or similar parts. Elements / components / steps using the same reference numerals or the same terms in different embodiments may be referred to mutually in the relevant descriptions.

[0038] Figure 1 This is a schematic diagram of a circuit block of a display device 100 according to an embodiment of the present invention. Figure 1 The display device 100 shown includes a scaler IC 110, a display panel 120, and a backlight device 130. The scaler IC 110 is coupled to the display panel 120. The scaler IC 110 can provide a video stream to the display panel 120 to display an image. The video stream includes multiple video frames. Each video frame includes a period of active video data and a blank period (e.g., a vertical blank period). In variable refresh rate (VRR) applications, the length of the blank period can vary between different video frames.

[0039] The backlight device 130 is coupled to the scaler integrated circuit 110 to receive information related to the duration of the valid video data. Figure 1 In the illustrated embodiment, the backlight device 130 includes a local dimming circuit 131 and a backlight module 132. The backlight module 132 includes N light zones for providing backlight to the display panel 120. Here, N is a positive integer determined according to the actual design. The local dimming circuit 131 is coupled to the backlight module 132 to control / drive each light zone. The local dimming circuit 131 is also coupled to a scaler integrated circuit 110 to receive information related to the duration of the valid video data.

[0040] Figure 2 This is a schematic flowchart illustrating an operation method of a backlight device according to an embodiment of the present invention. Please refer to... Figure 1 and Figure 2 In step S210, the local dimming circuit 131 can illuminate each of the N light zones of the backlight module 132 in a time-division manner during each of the multiple scan cycles to provide backlight to the display panel 120. For example, assuming N is 2 (the backlight module 132 is divided into 2 light zones), the local dimming circuit 131 can illuminate the first light zone (the second light zone is not illuminated) in the first half of the first scan cycle, and then the local dimming circuit 131 can illuminate the second light zone (the first light zone is not illuminated) in the second half of the first scan cycle. After all the light zones of the backlight module 132 have been scanned (illuminated in a time-division manner), the first scan cycle ends and the second scan cycle begins. The operation of the second scan cycle is similar to that of the first scan cycle, and therefore will not be described further. According to actual design, in some embodiments, the duration of these scan cycles of the backlight module 132 is equal.

[0041] In step S220, the local dimming circuit 131 can adjust the duration of these scanning cycles so that the duration of each of these scanning cycles is greater than or equal to the duration of the effective video data period of the display panel 120. According to actual design, in some embodiments, in addition to being greater than or equal to the duration of the effective video data period of the display panel 120, the duration of each scanning cycle of the backlight module 132 is also less than or equal to the duration of the display frame (video frame) of the display panel 120. Therefore, these scanning cycles of the backlight module 132 can be asynchronous with the display frame (video frame) of the display panel 120. In step S230, the local dimming circuit 131 can adjust the continuous illumination time of each of the N light zones so that the continuous illumination time of each of the N light zones is less than or equal to the quotient of the duration of the effective video data period divided by N.

[0042] Figure 3This is a circuit diagram illustrating a local dimming circuit 131 and a backlight module 132 according to an embodiment of the present invention. Figure 3 In the illustrated embodiment, the backlight module 132 is divided into N light zones, i.e. Figure 3 The light zones shown are LZ_1, LZ_2, ..., LZ_N. Each light zone LZ_1 to LZ_N contains different strings of light-emitting diodes or other light-emitting elements. The area dimming circuit 131 includes a microcontroller MCU3 and multiple drive channels. The microcontroller MCU3 uses dimming signal CH1 (signals COMP1 and ISET1) to control the first drive channel (resistor RC1, switch SW1, and resistor RS1) to determine the lighting time, duration, and brightness of light zone LZ_1. The microcontroller MCU3 also uses dimming signal CH2 (signals COMP2 and ISET2) to control the second drive channel (resistor RC2, switch SW2, and resistor RS2) to determine the lighting time, duration, and brightness of light zone LZ_2. Similarly, the microcontroller MCU3 can use the dimming signal CHn (signals COMPn and ISETn) to control the Nth drive channel (resistor RCn, switch SWn, and resistor RSn) to determine the lighting time, duration, and brightness of the light area LZ_N.

[0043] Figure 3 As shown, the backlight module 132 is divided into N light zones LZ_1 to LZ_N, for example, arranged sequentially from top to bottom in a one-dimensional manner, or arranged sequentially from left to right and then from top to bottom in a two-dimensional manner (Z-shape). The number of light zones N can be determined according to the actual design. For ease of explanation, the following embodiments will assume that the entire backlight module 132 is divided into 4 light zones LZ_1 to LZ_4.

[0044] Figure 4 This is a schematic diagram illustrating the driving timing of all four light zones LZ_1 to LZ_4 of the backlight module 132 being illuminated in a time-division manner, according to an embodiment of the present invention. Figure 4 The horizontal axis represents time. Figure 4 The diagram illustrates the vertical sync signal Vsync and the video stream VData provided by the scaler integrated circuit 110 to the display panel 120. The duration of two adjacent pulses of the vertical sync signal Vsync defines a display frame (e.g., ...). Figure 4 The duration of the displayed frame (F4) is shown. Each displayed frame includes a period of active video data and a period of silence, for example... Figure 4 The frame F4 shown includes the video data period VAD4 and the blank period BP4. Figure 4 The application scenario shown is under the condition of non-variable update rate (VRR), so the length of the blank period between different display frames is approximately the same.

[0045] The local dimming circuit 131 can time-division multiplex each of the four light zones LZ_1 to LZ_4 of the backlight module 132 in each scan cycle to provide backlight to the display panel 120. For example, the local dimming circuit 131 can... Figure 4 The scan cycle SP41 is shown to illuminate all four optical zones LZ_1 to LZ_4 at different times. Figure 4 The curves for light areas LZ_1 to LZ_4 show the time points, durations, and brightness of each light area being illuminated. Pulses indicate that a light area is illuminated (non-pulse areas indicate that the light area is not illuminated), the pulse width indicates the duration of illumination, and the pulse height indicates the brightness of the illuminated area. When any one of the light areas LZ_1 to LZ_4 is illuminated, the remaining light areas of LZ_1 to LZ_4 are not illuminated. After all four light areas LZ_1 to LZ_4 of the backlight module 132 have been scanned (illuminated in a time-division manner), the scan cycle SP41 ends, and the next scan cycle SP42 begins. The operation of scan cycle SP42 is similar to that of scan cycle SP41, and will not be described further. Figure 4 In the embodiment shown, the durations of these scanning cycles (e.g., SP41 and SP42) of the backlight module 132 are equal.

[0046] The local dimming circuit 131 can execute any algorithm according to the actual design to adjust the duration of these scan cycles (e.g., SP41 and SP42) so that the duration of each scan cycle of the backlight module 132 is greater than or equal to the duration of the video data period (e.g., VAD4) of the display panel 120, and less than or equal to the duration of the display frame (e.g., F4) of the display panel 120. Therefore, these scan cycles (e.g., SP41 and SP42) of the backlight module 132 can be asynchronous with the display frame (e.g., F4) of the display panel 120. The local dimming circuit 131 can execute any algorithm according to the actual design to adjust the continuous illumination time of each of the four light zones LZ_1 to LZ_4 of the backlight module 132 (e.g., ...). Figure 4 The durations CL41, CL42, CL43, and CL44 are shown, such that the duration of each continuous illumination is less than or equal to the quotient of the duration of the valid video data divided by N (where N is assumed to be "4"). For example, assuming the duration of the valid video data period VAD4 is T, then each of the continuous illumination durations CL41 to CL44 is less than or equal to T / 4. In this way, based on the backlight scanning (backlight black insertion) of the backlight module 132, the valid video data of each display frame is displayed by the backlight module 132 at most once. This embodiment can ensure that each valid video data is indeed displayed and can improve the motion blur problem of the display panel 120.

[0047] In some embodiments, the local dimming circuit 131 can also perform local dimming calculations according to the actual design to dynamically adjust the brightness of each of the four light zones LZ_1 to LZ_4 of the backlight module 132. Taking pulses P41, P42, P43, and P44 in the scanning cycle SP42 as an example, the local dimming circuit 131 can perform local dimming calculations to dynamically adjust the height of pulses P41 to P44, that is, adjust the brightness of each of the light zones LZ_1 to LZ_4. In other embodiments, the scaler integrated circuit 110 can perform local dimming calculations to control the backlight device 130 to dynamically adjust the brightness of each of the light zones LZ_1 to LZ_4.

[0048] Figure 5 This is a schematic diagram illustrating the driving timing of all four light zones LZ_1 to LZ_4 of the backlight module 132 being illuminated in a time-division manner, according to another embodiment of the present invention. Figure 5 The horizontal axis represents time. Figure 5 The diagram illustrates the vertical synchronization signal Vsync, video stream VData, display frame F5, video active data period VAD5, and blank period BP5, which can be referenced. Figure 4 The explanations of the vertical synchronization signal Vsync, video stream VData, display frame F4, video valid data period VAD4, and blank period BP4 are shown and can be extrapolated, so they will not be repeated here. Figure 5 The application scenario shown is under the condition of non-variable update rate (VRR), so the length of the blank period between different display frames is approximately the same.

[0049] Figure 5 The bright areas LZ_1 to LZ_4 of the area dimming circuit 131 at different time points in the scanning period SP51 are illustrated. Figure 5 The curves for light areas LZ_1 to LZ_4 show the time points, durations, and brightness at which the light areas are illuminated. After all four light areas LZ_1 to LZ_4 of the backlight module 132 have been scanned (illuminated in a time-division manner), the scan cycle SP51 ends, and the next scan cycle SP52 begins. The operation of scan cycle SP52 is similar to that of scan cycle SP51. Figure 5 The curves for optical regions LZ_1 to LZ_4 and the scan periods SP51 and SP52 shown can be referenced. Figure 4 The curves for optical regions LZ_1 to LZ_4 and the related explanations of scan periods SP41 and SP4 are shown, and analogies are drawn from them; therefore, they will not be repeated here. Figure 5 In the illustrated embodiment, the durations of these scan cycles (e.g., SP51 and SP52) of the backlight module 132 are equal. The duration of scan cycle SP51 is greater than or equal to the duration of VAD5 during the valid video data period, and the duration of scan cycle SP51 is less than or equal to the duration of display frame F5.

[0050] The local dimming circuit 131 can execute any algorithm according to the actual design to adjust the continuous illumination time of each of the four light zones LZ_1 to LZ_4 in the backlight module 132 (e.g., Figure 5 The parameters CL51, CL52, CL53, and CL54 are shown to ensure that the duration of each continuous illumination is less than or equal to the quotient of the duration of the valid video data divided by N (where N is assumed to be "4"). For example, the local dimming circuit 131 can perform black-insertion calculation to dynamically adjust the durations CL51 to CL54 of the continuous illumination of light zones LZ_1 to LZ_4. Alternatively, the scaler integrated circuit 110 can perform black-insertion calculation to control the backlight device 130 to dynamically adjust the durations CL51 to CL54 of the continuous illumination of light zones LZ_1 to LZ_4. Based on the backlight scanning (backlight black-insertion) of the backlight module 132, the valid video data of each display frame is displayed by the backlight module 132 at most once, and the motion blur problem of the display panel 120 can be improved.

[0051] In some embodiments, the local dimming circuit 131 can also perform local dimming calculations according to the actual design to dynamically adjust the brightness of each of the four light zones LZ_1 to LZ_4 of the backlight module 132. Taking pulses P51, P52, P53, and P54 in the scan cycle SP52 as an example, the local dimming circuit 131 can perform local dimming calculations to dynamically adjust the height of pulses P51 to P54, that is, adjust the brightness of each of the light zones LZ_1 to LZ_4. In other embodiments, the scaler integrated circuit 110 can perform local dimming calculations to control the backlight device 130 to dynamically adjust the brightness of each of the light zones LZ_1 to LZ_4.

[0052] Figure 6 This is a driving timing diagram illustrating, according to another embodiment of the present invention, that all four light zones LZ_1 to LZ_4 of the backlight module 132 are illuminated in a time-division manner. Figure 6 The horizontal axis represents time. Figure 6 The curves for the vertical synchronization signal Vsync, video stream VData, and optical zones LZ_1 to LZ_4 are plotted and can be used as a reference. Figure 4 The related explanations and analogies of the curves for the vertical synchronization signal Vsync, video stream VData, and optical zones LZ_1 to LZ_4 are shown below, so they will not be repeated here. Unlike... Figure 4 The illustrated embodiment is characterized in that, Figure 6 The illustrated embodiment operates in a variable update rate (VRR) application environment, therefore Figure 6 The duration of the blank periods in different display frames can vary.

[0053] Figure 7This is a driving timing diagram illustrating, according to another embodiment of the present invention, that all four light zones LZ_1 to LZ_4 of the backlight module 132 are illuminated in a time-division manner. Figure 7 The horizontal axis represents time. Figure 7 The curves for the vertical synchronization signal Vsync, video stream VData, and optical zones LZ_1 to LZ_4 are plotted and can be used as a reference. Figure 5 The related explanations and analogies of the curves for the vertical synchronization signal Vsync, video stream VData, and optical zones LZ_1 to LZ_4 are shown below, so they will not be repeated here. Unlike... Figure 5 The illustrated embodiment is characterized in that, Figure 7 The illustrated embodiment operates in a variable update rate (VRR) application environment, therefore Figure 7 The duration of the blank periods in different display frames can vary.

[0054] In summary, the local dimming circuit 131 described in the above embodiments provides backlight to the display panel 120 by illuminating different light zones in a time-division manner. By utilizing the technique of zonal backlight illumination, the local dimming circuit 131 can reduce the image persistence characteristics of the display panel 120 and improve the motion blur problem of the display panel. Furthermore, this invention is applicable not only to general non-variable refresh rate (VRR) scenarios but also to variable refresh rate (VRR) application environments.

[0055] The present invention has been described in the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A backlight device, characterized in that, include: The backlight module includes N light zones to provide backlight to the display panel, where N is a positive integer; as well as A local dimming circuit, coupled to the backlight module, is used to illuminate each of the N light zones in a time-division manner during each of a plurality of scan cycles; wherein the plurality of scan cycles are asynchronous with a plurality of display frames of the display panel to adapt to the variable refresh rate mode and non-variable refresh rate mode of the display panel; the duration of each of the plurality of scan cycles is greater than or equal to the duration of the video data period of the display panel, and the duration of continuous illumination of each of the N light zones is less than or equal to the quotient of the duration of the video data period divided by N.

2. The backlight device as claimed in claim 1, characterized in that, The durations of these multiple scan cycles are equal.

3. The backlight device as described in claim 1, characterized in that, The duration of each of the multiple scan cycles is less than or equal to the duration of the display frame on the display panel.

4. The backlight device as claimed in claim 1, characterized in that, The dimming circuit in this area performs dimming calculations to dynamically adjust the brightness of each of the N light zones; or, the dimming circuit in this area performs black insertion calculations to dynamically adjust the continuous illumination time of each of the N light zones.

5. A method for operating a backlight device, characterized in that, include: The local dimming circuit of the backlight device illuminates each of the N light zones of the backlight module of the backlight device in a time-division manner in each of a plurality of scanning cycles to provide backlight to the display panel, where N is a positive integer; The multiple scan cycles are asynchronous with the multiple display frames of the display panel to adapt to the variable refresh rate mode and non-variable refresh rate mode of the display panel. The duration of the multiple scan cycles is adjusted by the dimming circuit of the area so that the duration of each of the multiple scan cycles is greater than or equal to the duration of the video effective data of the display panel. as well as The dimming circuit in that area adjusts the continuous illumination time of each of the N light zones so that the continuous illumination time of each of the N light zones is less than or equal to the quotient of the duration of the valid video data divided by N.

6. The operating method as described in claim 5, characterized in that, The durations of these multiple scan cycles are equal.

7. The operating method as described in claim 5, characterized in that, The duration of each of the multiple scan cycles is less than or equal to the duration of the display frame on the display panel.

8. The operating method as described in claim 5, characterized in that, Also includes: The dimming circuit in this area performs dimming calculations for a specific area to dynamically adjust the brightness of each of the N light zones; or, The dimming circuit in this area performs a black-insertion calculation to dynamically adjust the continuous lighting time of each of the N light zones.

9. A display device, characterized in that, include: Display panel; A scaler integrated circuit is coupled to the display panel; as well as The backlight device as described in any one of claims 1 to 4 is coupled to the zoomer integrated circuit.

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