Cooperative control method for black insertion and variable refresh rate in LED backlight display equipment

Abstract

The invention discloses a black frame insertion and variable refresh rate cooperative control method in LED backlight display equipment, which comprises the following steps: S1, setting an independent channel delay duration for each LED backlight channel, and setting an effective display duration and a black frame insertion duration at the same time; s2, after the driving chip receives the frame synchronization signal, single-frame timing is started, and each LED backlight channel firstly carries out timing according to own preset channel delay duration; s3, starting black frame insertion duration timing of the LED channel, and closing backlight illumination of the LED channel within the black frame insertion duration; s4, then starting the effective display duration of the LED channel, and starting the gray scale brightness backlight illumination of the LED channel according to the image data within the effective display duration; and S5, then starting the gray scale display duration of the LED channel, and emitting light by the LED channel at fixed gray scale brightness within the gray scale display duration until the next frame of synchronous signal arrives.

Description

Technical Field

[0001] This invention relates to the field of LED backlight technology, and in particular to a method for the coordinated control of black insertion and variable refresh rate in an LED backlight display device. Background Technology

[0002] Liquid crystal displays (LCDs) require liquid crystal molecules to flip for each frame displayed. High refresh rates can cause blurry, ghosting images when playing fast-moving scenes, negatively impacting the user experience. Traditional black frame insertion (BFI) involves inserting a black frame between two normal frames to mask the lingering gray image and eliminate ghosting, improving the viewing experience. However, traditional black frame insertion requires a sufficiently fast response time from the LCD; otherwise, the inserted black frame is easily noticeable to the human eye, causing flickering.

[0003] Variable Refresh Rate (VRR) is a new technology for display panels that allows the refresh rate to adaptively change based on the current processing speed of video providers, such as graphics processing units (GPUs). This avoids visual issues like screen tearing and image retention that can occur when the GPU cannot output image frames in time. Variable refresh rate displays provide a better user experience, especially for gamers, as the signal enhances the visual quality of games and reduces or eliminates issues like lag, stuttering, and frame tearing.

[0004] Based on the characteristics of BFI and VRR technologies mentioned above, implementing black pixel insertion (BPI) on variable refresh rate display panels in existing technologies makes it difficult to achieve good display results. In synchronous backlight control schemes, the backlight control signal is synchronized with the vertical sync signal (Vsync, a pulse signal applied between two frames indicating the end of the previous frame and the beginning of the new frame; its frequency is consistent with the screen refresh rate). Therefore, since the frame period (i.e., the period of the vertical sync signal Vsync) is variable, performing BFI in different frame periods will cause inconsistent backlight zone currents in the backlight control signal. The continuously changing backlight zone currents will produce backlight flicker, which the user perceives as image flickering. Therefore, implementing BPI on variable refresh rate panels, in addition to causing a decrease in brightness due to the BPI technology itself, can easily lead to backlight flicker.

[0005] In existing technologies, either the TCON dynamically detects the graphics card's vsync signal, calculates the current frame period, and automatically adjusts the black frame insertion interval; or the software reads the graphics card's frame rate data in real time and adjusts the proportion of black frames to balance blur and brightness. However, the above methods result in brightness loss: BFI causes a 30%-50% reduction in brightness, which is more noticeable at high frame rates; or hardware-level synchronization solutions require high-end TCONs, leading to higher hardware costs.

[0006] Therefore, a new LED backlight control technology is needed in the existing technology to enable black insertion technology to be implemented simultaneously under variable refresh rate and to achieve better display effect, that is, to maintain high image brightness while avoiding backlight flicker. Summary of the Invention

[0007] The technical objective of this invention is to enable black bar insertion technology to be implemented simultaneously under variable refresh rates and to achieve better display effects, namely, to maintain high image brightness while avoiding backlight flicker.

[0008] Based on the above technical objectives, this invention provides a method for coordinated control of black insertion and variable refresh rate in an LED backlight display device, the coordinated control method comprising:

[0009] S1, set an independent channel delay duration for each LED backlight channel, and simultaneously set the effective display duration and black frame insertion duration;

[0010] S2, after the driver chip receives the frame synchronization signal, it starts single frame timing. Each LED backlight channel first times according to its own preset channel delay time.

[0011] S3, when the channel delay time of each LED backlight channel is completed, start the black frame insertion time timer for that LED channel, and turn off the backlight illumination of that LED channel during the black frame insertion time;

[0012] S4, when the black frame insertion time of each LED backlight channel is completed, the effective display time of the LED channel is started, and the grayscale brightness backlight illumination of the LED channel is started according to the image data within the effective display time.

[0013] S5, when the effective display time of each LED backlight channel is completed, the grayscale display time of that LED channel is started. During the grayscale display time, the LED channel emits light at a fixed grayscale brightness until the next frame synchronization signal arrives.

[0014] In one embodiment, the channel delay duration, effective display duration, and black frame insertion duration are fixed time lengths.

[0015] In one embodiment, the channel delay duration, effective display duration, and black frame insertion duration are a certain number of cycles of the PWM dimming signal.

[0016] In one embodiment, the total duration of the channel delay, effective display duration, and black frame insertion duration is less than or equal to the frame cycle duration corresponding to the highest refresh rate.

[0017] In one embodiment, the total duration of the channel delay, effective display duration, and black frame insertion duration is adjusted according to the current refresh rate of the display device, and the total duration is kept less than the frame period duration of the current refresh rate.

[0018] In one embodiment, during the channel delay period, each LED backlight channel in the LED backlight panel still drives the LED light-emitting unit in the channel to emit light according to the fixed grayscale brightness within the grayscale display period of the previous image.

[0019] In one embodiment, the fixed grayscale brightness can be automatically calculated and generated by the LED driver chip, or pre-configured by the host computer controlling the backlight timing.

[0020] The beneficial effects of this invention are as follows:

[0021] a) Saves hardware resources: The driver chip realizes the automatic calculation of grayscale brightness of each channel under different brightness levels, without the need for the host computer to perform a large amount of data calculation and processing, which reduces the hardware resource occupation of the host computer (such as MCU) and simplifies the software logic.

[0022] b) Highly efficient brightness adjustment: Grayscale brightness is calculated locally by the driver chip and applied in real time, eliminating the need for frequent transmission of large amounts of configuration data from the host computer, significantly shortening the time for brightness adjustment to take effect and improving the response speed of scene switching;

[0023] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a schematic diagram of the structure of the LED backlight panel of the present invention;

[0026] Figure 2This is a schematic diagram of the backlight timing of the LED backlight panel of the present invention;

[0027] Figure 3 This is a schematic diagram of the collaborative control method for black insertion and variable refresh rate of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And when a second element, component, area, layer, or portion is discussed, it does not imply that the first element, component, area, layer, or portion necessarily exists in this invention.

[0030] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0032] Example 1

[0033] like Figure 1-3 As shown, the LED backlight panel of the present invention includes multiple LED backlight channels and a backlight timing controller. Multiple LED driver chips are disposed in the LED backlight channels. Each LED driver chip is connected to at least one LED light-emitting unit. The LED driver chip receives data sent by the backlight timing controller to drive the LED light-emitting unit to perform backlight illumination.

[0034] The collaborative control method for black insertion and variable refresh rate of the present invention includes:

[0035] S1, set an independent channel delay duration for each LED backlight channel, and simultaneously set the effective display duration and black frame insertion duration. The LED backlight panel of this invention uses the frame synchronization signal vsync for displaying image data as the reference signal for the frame refresh cycle, used to synchronize the dynamic adjustment of the frame rate between image black frame insertion, display timing, and variable refresh rate (VRR). To address the characteristic of inconsistent liquid crystal flip points among multiple LED driving channels, this invention introduces three timing parameters to support independent channel configuration:

[0036] 1. Channel Delay Duration (T_DELAY): Each LED driver channel is configured independently to accommodate the differences in LCD reversal across different channels, ensuring synchronized alignment of multi-channel images and avoiding uneven brightness.

[0037] 2. Effective display duration (T_WHITE): The duration of normal display within a single frame, which determines the visual brightness of the image.

[0038] 3. Black Frame Insertion Duration (T_BLANK): The timing of inserting a black frame within a single frame. This is a core parameter for BFI technology to reduce motion blur, and it works in conjunction with T_WHITE to balance image sharpness and brightness. This is because black frame insertion reduces overall brightness.

[0039] The above three parameters support both absolute time and relative time configuration modes.

[0040] (1) Absolute time configuration mode: adopts a fixed clock period definition, such as 4μs, 8μs, 16μs, 32μs, etc., with high timing accuracy, suitable for scenarios with strict requirements for screen synchronization (such as vehicle display, industrial control screen).

[0041] (2) Relative time configuration mode: Defined based on the PWM period, without needing to pay attention to the absolute clock, directly bound to the PWM output period of the driver chip, with flexible configuration and stronger compatibility.

[0042] The LED backlight panel of the present invention has:

[0043] (1) High-frequency PWM output capability: The driver chip usually adopts 20KHz~40KHz high-frequency PWM dimming to avoid low-frequency flicker, while providing sufficient resolution for multi-stage timing within a single frame;

[0044] (2) Frame refresh rate (VSYNC) range: Supports a lower frame rate of 40~60Hz (low power static scene) and an upper frame rate of 144~240Hz (high dynamic clarity scene).

[0045] (3) Mapping relationship between PWM period and frame period: Since the PWM frequency is much higher than the frame refresh frequency, a single frame time can contain dozens to hundreds of PWM periods, providing support for the fine configuration of T_DELAY, T_WHITE, and T_BLANK (for example, 60Hz frame period ≈ 16.7ms, 40KHz PWM period = 25μs, a single frame can accommodate about 668 PWM periods).

[0046] In this invention, the total duration of the channel delay, effective display duration, and black frame insertion duration is less than or equal to the frame period duration. Specifically, either the total duration of the channel delay, effective display duration, and black frame insertion duration is less than or equal to the frame period duration corresponding to the highest refresh rate, or the total duration of the channel delay, effective display duration, and black frame insertion duration is adjusted according to the current refresh rate of the display device, while maintaining the total duration less than the frame period duration of the current refresh rate.

[0047] S2, after the driver chip receives the frame synchronization signal, it starts single-frame timing. Each LED backlight channel first times according to its own preset channel delay duration. That is, when the backlight timing controller receives the frame synchronization signal vsync for the displayed image data, all LED backlight channels begin to enter an independent delay waiting state: each LED backlight channel counts independently according to its own configured channel delay duration T_DELAY parameter, and waits until the specified time to complete the LCD flip-up preparation.

[0048] S3, when the channel delay timer for each LED backlight channel finishes, the black frame insertion timer for that LED channel is started, and the backlight illumination of that LED channel is turned off during the black frame insertion time. That is, during the black frame insertion time, the LED driver chip turns off the corresponding LED light-emitting unit (or outputs the lowest brightness), realizing black frame insertion and eliminating the ghosting caused by visual persistence.

[0049] S4, when the black frame insertion time of each LED backlight channel has expired, the effective display time of that LED channel is activated. Within the effective display time, the grayscale brightness backlight of that LED channel is activated according to the image data. That is, the LED driver chip turns on the LED light-emitting unit and outputs the effective frame grayscale brightness corresponding to the displayed image data, ensuring normal visibility and brightness performance of the image.

[0050] S5, when the effective display time of each LED backlight channel is completed, the grayscale display time of that LED channel is activated. During the grayscale display time, the LED channel emits light at a fixed grayscale brightness until the next frame synchronization signal arrives. That is, during the channel delay time in this invention, each LED backlight channel in the LED backlight panel still drives the LED light-emitting unit in this channel to emit light according to the fixed grayscale brightness during the grayscale display time of the previous image.

[0051] In this invention, maintaining a fixed grayscale brightness for the LED channel within the specified grayscale display duration is a crucial technical means to achieve a black-insertion display effect. This fixed grayscale brightness can be automatically calculated and generated by the LED driver chip, or pre-configured by a host computer controlling the backlight timing. Wherein:

[0052] (1) Automatic calculation of LED driver chip: The LED driver chip uses the built-in grayscale brightness algorithm to automatically calculate the brightness corresponding to each grayscale based on the input basic brightness command (such as brightness reference value), combined with the current PWM frequency and the effective display duration T_WHITE duration.

[0053] (2) Host computer pre-configuration: The host computer pre-calculates grayscale brightness data for different scenarios, transmits the configuration data to the driver chip through the OWC peripheral, and writes it into the corresponding hardware register. This is suitable for scenarios with extremely high brightness accuracy requirements (such as professional display devices).

[0054] This invention also provides grayscale brightness fine-tuning optimization: based on the automatic calculation by the driver chip, a brightness fine-tuning parameter BRT_CMP is introduced to provide differentiated compensation for different dimming methods (such as global dimming, local dimming, and zone dimming). Its function is to correct brightness deviations under different dimming modes and solve problems such as uneven brightness across multiple channels and low grayscale flicker. Its configuration method includes: the brightness fine-tuning parameter BRT_CMP can be configured independently for each channel, written into the driver chip's dedicated fine-tuning register, and superimposed on the automatically calculated grayscale brightness to take effect, without requiring modification to the core algorithm.

[0055] The formula for automatically calculating grayscale brightness by the driver chip is as follows:

[0056]

[0057] BRT1 is the brightness baseline value. Based on this, the brightness fine-tuning parameter BRT_CMP is added to fine-tune the grayscale brightness for different dimming methods. Therefore, the driver chip's automatic grayscale brightness calculation formula is corrected as follows:

[0058]

[0059] This invention can be any possible system, method, and / or computer program product at the level of integrated technical detail. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions thereon for causing a processor to execute aspects of the invention.

[0060] A computer-readable storage medium can be a tangible device that can hold and store instructions used by an instruction execution device. The computer-readable storage medium can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: a portable computer floppy disk, a hard disk, random access memory (RAM), read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), a portable optical disc read-only memory (CD-ROM), a digital universal disc (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or raised structure in a notch on which instructions are recorded, and any suitable combination of the foregoing. A computer-readable storage medium, as used herein, should not be construed as a transient signal itself, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0061] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to a suitable computing / processing device, or via a network, such as the Internet, a local area network (LAN), a wide area network (WAN), and / or a wireless network, to an external computer or external storage device. This network may include copper transmission cables, optical fiber transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to a computer-readable storage medium within the suitable computing / processing device.

[0062] Computer-readable program instructions used to perform the operations of this invention may be assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, configuration data for integrated circuits, or source code or object code written in one or more programming languages ​​and any combination of procedural programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet through an Internet service provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) may execute the computer-readable program instructions by utilizing state information from the computer-readable program instructions to personalize the electronic circuitry and thereby perform aspects of the invention.

[0063] This document describes aspects of the invention with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0064] These computer-readable program instructions can be provided to a computer's processor or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, create a mechanism for implementing flowcharts and / or blocks. Figure 1Means for the functions / actions specified in one or more boxes. These computer-readable program instructions may also be stored in a computer-readable storage medium capable of guiding a computer, a programmable data processing apparatus and / or other apparatus operating in a particular manner, such that the computer-readable storage medium storing the instructions includes an article of manufacture comprising instructions for implementing aspects of the functions / actions specified in the flowchart and / or block diagram boxes.

[0065] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other apparatus to cause a series of operational steps to be performed on the computer, other programmable devices or other apparatus for producing computer-implemented processes, such that the instructions executed on the computer, other programmable devices or other apparatus perform the functions / actions specified in the flowchart and / or block diagram boxes.

[0066] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of instructions comprising one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions indicated in a block may occur outside the order indicated in the diagram. For example, two blocks shown consecutively may actually be completed as a single step, executed concurrently, substantially concurrently, in a manner that overlaps partially or entirely in time, depending on the functions involved, or sometimes these blocks may be executed in reverse order. It will also be noted that each block illustrated in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action or executes a combination of dedicated hardware and computer instructions.

[0067] This application describes embodiments with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0068] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0069] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0070] The above description is merely a specific implementation example of the present invention, and the scope of protection of the present invention is not limited thereto. Any modifications or substitutions made to the present invention by those skilled in the art within the technical specifications described herein should be within the scope of protection of the present invention.

Claims

1. A method for cooperative control of black frame insertion and variable refresh rate in an LED backlight display device, characterized in that, The cooperative control method comprises: S1, setting an independent channel delay time length for each LED backlight channel, and simultaneously setting an effective display time length and a black frame insertion time length; S2, after the driving chip receives a frame synchronization signal, starting single-frame timing, and each LED backlight channel first performs timing according to the channel delay time length preset by itself; S3, when the channel delay time length timing of each LED backlight channel is completed, starting the black frame insertion time length timing of the LED channel, and the backlight illumination of the LED channel is turned off within the black frame insertion time length; S4, when the black frame insertion time length timing of each LED backlight channel is completed, starting the effective display time length of the LED channel, and the gray scale brightness backlight illumination of the LED channel is started according to the image data within the effective display time length; S5, when the effective display time length timing of each LED backlight channel is completed, starting the gray scale display time length of the LED channel, and the LED channel emits light at a fixed gray scale brightness within the gray scale display time length until the next frame synchronization signal arrives.

2. The collaborative control method of claim 1, wherein, The channel delay time length, the effective display time length and the black frame insertion time length adopt fixed time lengths.

3. The collaborative control method of claim 1, wherein, The channel delay time length, the effective display time length and the black frame insertion time length are a certain number of cycle numbers of PWM dimming signals.

4. The collaborative control method of claim 1, wherein, The total time length of the channel delay time length, the effective display time length and the black frame insertion time length is less than or equal to the frame period time length corresponding to the highest refresh rate.

5. The collaborative control method of claim 1, wherein, The total time length of the channel delay time length, the effective display time length and the black frame insertion time length is adjusted according to the current refresh rate of the display device, and the total time length is kept less than the frame period time length of the current refresh rate.

6. The collaborative control method of claim 1, wherein, In the channel delay time length, each LED backlight channel in the LED backlight panel still drives the LED light emitting unit in the channel to emit light at the fixed gray scale brightness in the gray scale display time length of the previous image.

7. The collaborative control method of claim 1, wherein, The fixed gray scale brightness can be automatically calculated and generated by the LED driving chip, or preconfigured by the upper computer of the backlight timing control.

8. An electronic device comprising a memory and a processor; wherein, The memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the steps of the method of any one of claims 1-7.

9. A computer readable storage medium having stored thereon computer instructions, wherein, The computer instructions are executed by the processor to implement the steps of the method of any one of claims 1-7.

10. A computer program product comprising computer programs / instructions, which, when executed by a processor, implement the steps of the method of any one of claims 1-7.

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