Display device and driving method thereof

Abstract

A display device is provided. The display device includes: a display panel; a backlight unit outputting light; a backlight driving unit driving the backlight unit; and at least one processor connected to the display panel, the backlight unit, and the backlight driving unit to control the display device. The at least one processor identifies an output frequency of the synchronization signal that varies according to a variable refresh rate of the variable frequency image, and outputs the synchronization signal to the backlight driving unit at a frequency higher than the identified output frequency of the synchronization signal according to preset information. The backlight driving unit drives the backlight unit by identifying a dimming interval according to a variable refresh rate on the basis of receiving the synchronization signal.

Description

Technical Field

[0001] The present disclosure relates to a display device and a driving method thereof, and more particularly, to a display device including a backlight and a driving method thereof. Background Art

[0002] In a display, an "afterimage" refers to a distortion generated in a displayed image. An afterimage may be caused by an optical illusion of the human eye, and an afterimage may be found in an image or a display. Motion blur is an afterimage in which the boundary of an object moving in a moving image is blurred and a distortion is generated in the image, and a method for solving motion blur is motion blur reduction.

[0003] Motion blur reduction is a method of reducing the generation of an optical illusion by arranging black screens at several positions according to a reproduction frequency (scanning rate) of a display. For example, by turning off a backlight for a short time during a period of displaying a first frame to provide a black image, and when the human eye remembers the image before seeing the next screen, the previously remembered image is a black image, and thus, the first frame does not appear as an afterimage in a second frame displayed after the black image. Summary of the Invention

[0004] Technical Solution

[0005] According to an aspect of the present disclosure, a display device includes: a display panel; a backlight unit configured to output light; a backlight driver configured to drive the backlight unit by identifying a dimming section of the backlight unit corresponding to a variable refresh rate of an image based on a received sync signal; a memory storing at least one instruction; and at least one processor operably connected to the display panel, the backlight unit, the backlight driver, and the memory. The at least one processor is configured to execute the at least one instruction to: identify a first output frequency of the sync signal that varies based on a variable refresh rate of an image, and output the sync signal to the backlight driver at a second output frequency based on predetermined information, the second output frequency being a frequency higher than the first output frequency, wherein the backlight driver is configured to drive the backlight unit corresponding to the variable refresh rate of the image based on receiving the sync signal at the second output frequency.

[0006] The predetermined information may include information for identifying the sync signal and a variable frequency of an image based on a variable frequency among a plurality of sync signals received at the backlight driver.

[0007] The at least one processor may also be configured to execute at least one instruction to: output a synchronization signal to the backlight driver at a frequency corresponding to n times the first output frequency based on predetermined information, where n is a positive integer, and where the backlight driver is configured to drive the backlight unit by identifying a dimming section corresponding to the variable refresh rate of the image based on the predetermined information and the reception point of the synchronization signal.

[0008] The backlight driver may also be configured to: identify a first synchronization signal among a plurality of synchronization signals received from the at least one processor as a timing signal for power-cycling the backlight unit based on the predetermined information, and identify a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on the first synchronization signal and a second synchronization signal received at a time point different from the first synchronization signal.

[0009] The backlight driver may also be configured to: identify a variable frequency of the image corresponding to the variable refresh rate of the image based on a time interval between receiving the first synchronization signal and the second synchronization signal, and identify a dimming section of the backlight unit based on the variable frequency of the image.

[0010] The at least one processor may also be configured to execute at least one instruction to: identify the n value based on at least one of a minimum value, a maximum value, a middle value, or an average value of the variable refresh rate of the image.

[0011] The at least one processor may also be configured to execute at least one instruction to: identify the n value based on the brightness information of the image.

[0012] The at least one processor may also be configured to execute at least one instruction to: output a synchronization signal to the backlight driver at a second output frequency based on the predetermined information, the second frequency corresponding to n times the first output frequency, where n is 2. The backlight driver may also be configured to: identify a variable frequency of the image corresponding to the variable refresh rate of the image based on n being 2 and a time interval between receiving the first synchronization signal and a second synchronization signal consecutive to the first synchronization signal, and identify a dimming section of the backlight unit based on the variable frequency of the image.

[0013] The at least one processor may also be configured to execute at least one instruction to: output a synchronization signal to the backlight driver at a frequency corresponding to a first multiple (n1) of the first frequency value based on the first output frequency having a first frequency value, and output a synchronization signal to the backlight driver at a frequency corresponding to a second multiple (n2) of the second frequency value based on the first output frequency having a second frequency value, where n1 and n2 are different integers.

[0014] At least one processor may also be configured to execute at least one instruction to: vary the current applied in a dimming section of a backlight unit to compensate for variations in the brightness of an image corresponding to a variable refresh rate.

[0015] According to one aspect of the present disclosure, a method of driving a display device includes: identifying a first output frequency of a synchronization signal that varies based on a variable refresh rate of an image; outputting the synchronization signal to a backlight driver at a second output frequency based on predetermined information, the second output frequency being a frequency higher than the first output frequency; and driving the backlight unit by identifying a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on the synchronization signal received at the backlight driver.

[0016] The predetermined information may include: information for identifying the variable frequency of the synchronization signal and the image based on the variable frequency among a plurality of synchronization signals received at the backlight driver.

[0017] Outputting the synchronization signal to the backlight driver at the second output frequency may include: outputting the synchronization signal to the backlight driver at a frequency corresponding to n times the first output frequency based on the predetermined information, where n is a positive integer, and identifying a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on the predetermined information and the reception point of the synchronization signal.

[0018] Driving the backlight unit may include: identifying a first synchronization signal among a plurality of synchronization signals received at the backlight driver as a timing signal for power cycling the backlight unit based on the predetermined information, and identifying a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on the first synchronization signal and a second synchronization signal received at a time point different from the first synchronization signal.

[0019] According to one aspect of the present disclosure, a non-transitory computer-readable medium stores computer-readable program code or instructions executable by a processor to perform a method of driving a display device. The method includes: identifying a first output frequency of a synchronization signal that varies based on a variable refresh rate of an image; outputting the synchronization signal to a backlight driver at a second output frequency based on predetermined information, the second output frequency being a frequency higher than the first output frequency; and driving the backlight unit by identifying a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on the synchronization signal received at the backlight driver. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0021] Figure 1 is a diagram showing characteristics of a display panel according to one or more embodiments of the present disclosure;

[0022] Figure 2 is a block diagram showing a configuration of a display device according to one or more embodiments of the present disclosure;

[0023] Figure 3 is a diagram showing a display driving method according to one or more embodiments of the present disclosure;

[0024] Figure 4 is a diagram showing a display driving method according to one or more embodiments of the present disclosure;

[0025] Figure 5 is a diagram showing a display driving method according to one or more embodiments of the present disclosure;

[0026] Figure 6 is a diagram showing a method for identifying a backlight dimming section based on a synchronization signal according to an embodiment;

[0027] Figure 7A and Figure 7B is a diagram showing a method for identifying a dimming duty ratio of each backlight block during local dimming according to an embodiment;

[0028] Figure 8 and Figure 9 is a diagram showing a display driving method according to one or more embodiments of the present disclosure;

[0029] Figure 10 is a diagram showing a display driving method according to one or more embodiments of the present disclosure;

[0030] Figure 11 and Figures 12A to 12C is a diagram showing a display driving method according to one or more embodiments of the present disclosure; and

[0031] Figure 13 is a diagram showing a detailed configuration of a display device according to one or more embodiments of the present disclosure. Detailed Description of the Embodiments

[0032] Terms used in the present disclosure will be briefly described, and then embodiments of the present disclosure will be described in detail.

[0033] The terms used in this disclosure are only for describing specific embodiments, and it should be understood that these terms are not intended to limit the scope of this disclosure. However, these terms may change according to the intentions of those skilled in the art working in the relevant field, previous court judgments, the emergence of new technologies, etc. In addition, in specific cases, there may be terms designated by the applicant himself / herself, and in such cases, the meanings of these terms will be described in detail in the relevant descriptions of this disclosure. Therefore, the terms used in this disclosure should be defined based on the meaning of the term and the overall content of this disclosure, rather than just based on the name of the term.

[0034] Also, in this specification, expressions such as "have", "may have", "include", and "may include" indicate the existence of such characteristics (e.g., elements such as numbers, functions, operations, and components), and do not exclude the existence of additional characteristics.

[0035] In addition, in this disclosure, expressions such as "A or B", "at least one of A and / or B", or "one or more of A and / or B" may include all possible combinations of the listed items. For example, "A or B", "at least one of A and B", or "at least one of A or B" may refer to all of the following cases: (1) only A, (2) only B, or (3) both A and B.

[0036] Furthermore, the expressions "first", "second", etc. used in this specification may be used to describe various elements regardless of any order and / or degree of importance. In addition, such expressions are only used to distinguish one element from another element and are not intended to limit the element.

[0037] In addition, the description in this disclosure that one element (e.g., the first element) is "(operatively or communicatively) coupled" or "connected to" another element (e.g., the second element) should be interpreted to include the case where one element is directly coupled to another element and the case where one element is coupled to another element through yet another element (e.g., the third element).

[0038] In addition, depending on the situation, the expression "configured to" used in this disclosure may be used interchangeably with other expressions such as "suitable for", "capable of...", "designed to", "adapted to", "manufactured to", and "able to", etc. The term "configured to" may not necessarily mean that the device is "specially designed" in terms of hardware.

[0039] Conversely, in some cases, the expression "the apparatus is configured to" may mean that the device "is capable of" performing an operation together with another device or component. For example, the phrase "the processor is configured to execute A, B, and C" may refer to a dedicated processor (e.g., an embedded processor) for performing the corresponding operations, or a general-purpose processor (e.g., a CPU or an application processor) that can execute the corresponding operations by executing one or more software programs stored in a memory device.

[0040] Also, singular expressions include plural expressions as long as they do not have significantly different meanings in the context. In addition, in this disclosure, terms such as "including" and "consisting of" should be interpreted as specifying the presence of such features, numbers, steps, operations, elements, components, or combinations thereof described in the specification, but not precluding the possibility of the presence or addition of one or more of other features, numbers, steps, operations, elements, components, or combinations thereof.

[0041] In addition, in the embodiments of this disclosure, a "module" or a "component" performs at least one function or operation and can be implemented as hardware or software, or as a combination of hardware and software. And, except for "modules" or "parts" that need to be implemented as specific hardware, multiple "modules" or multiple "parts" can be integrated into at least one module and implemented as at least one processor.

[0042] Various elements and regions in the drawings are schematically shown. Therefore, the technical idea of this disclosure is not limited by the relative sizes or intervals shown in the drawings.

[0043] Hereinafter, embodiments of this disclosure will be described in detail with reference to the drawings, in which like reference numerals always consistently denote corresponding features. Figure 1 is a diagram showing characteristics of a display panel according to one or more embodiments of this disclosure.

[0044] A display panel that realizes image display by using a backlight such as a quantum light-emitting diode (QLED) panel, a liquid crystal display (LCD), etc. maintains an output image signal during a specific time period for displaying an image. However, although eye movement has continuous motion, during the section where the output signal is maintained, the recognized image is in a halt state, and thus motion blur is caused thereby. Here, motion blur refers to the phenomenon that the boundaries of a moving object are not distinguishable but appear to overlap, and thus it looks like image dragging. As Figure 1 shown, in Image 10, in an area of an object with large motion or an area of an object with clear boundaries, the motion blur phenomenon can be more easily recognized.

[0045] As a method for motion blur reduction (MBR), backlight dimming is used. Backlight dimming is a method of quickly adjusting the duty on / off of the backlight to adapt to the screen scanning rate corresponding to the vertical synchronization (Vsync) frequency, which is the standard and input point at which the image is refreshed. Thereby, the panel afterimage generated during fast motion is reduced, and the user can feel a faster panel response speed.

[0046] Backlight dimming can be divided into local dimming and global dimming. In local dimming, the screen is divided into multiple regions, and the backlight lighting time is controlled individually for each region. In global dimming, the backlight lighting time of the entire screen is controlled integrally.

[0047] For example, the backlight unit 120 can be implemented as a direct - type backlight unit 120 - 1 or an edge - type backlight unit 120 - 2. For example, the direct - type backlight unit 120 - 1 can be implemented in such a structure that multiple optical sheets and a diffuser plate are laminated under the display panel 110, and multiple light sources are arranged under the diffuser plate. For example, the edge - type backlight unit 120 - 2 can be implemented in such a structure that multiple optical sheets and a light guiding plate are laminated under the display panel 110, and multiple light sources are arranged on the side surface of the light guiding plate. According to an embodiment, in the case of using local dimming, each of the multiple backlight blocks included in the backlight unit 120 can be driven separately according to the dimming duty based on the image information of the corresponding screen region. According to another embodiment, in the case of using global dimming, the multiple backlight blocks included in the backlight unit 120 are not controlled separately and can control the backlight lighting time integrally.

[0048] In the case of outputting an image by using the Vsync function, if a high - frame - rate image signal is output from the GPU, due to the frame difference between the frame rate of the original image caused by Vsync and the fixed refresh rate, jitter / stuttering phenomena may occur. To solve this problem, a variable refresh rate (VRR) technology for outputting an image to adapt to the frame rate of the original image is being applied. In addition, the VRR technology is being applied to correspond to the variable frame rate of the source device.

[0049] When the backlight unit 120 is turned on / off at a fixed refresh rate for implementing motion blur reduction (MBR), the current root mean square (RMS) value applied to the backlight decreases. As a result, a phenomenon of lower brightness occurs. In addition, when MBR is implemented with a variable refresh rate, when the refresh rate changes and the duty ratio is attempted to be fixed, the current RMS value changes each time according to the change in the Vsync value, and an irregular brightness phenomenon of the display may occur.

[0050] Figure 2 is a block diagram showing the configuration of a display device according to one or more embodiments of the present disclosure.

[0051] Refer to Figure 2 , the display device 100 includes a display panel 110, a backlight unit 120, a backlight driver 130, and at least one processor 140.

[0052] The display device 100 may be implemented as a smart phone, a tablet computer, a smart TV, an Internet TV, a network TV, an Internet protocol TV (IPTV), a signage, a PC, a monitor, etc., but is not limited thereto, and the display device 100 may be implemented as various types of devices equipped with a display function, such as a large format display (LFD), a digital signage, a digital information display (DID), a video wall, a projector display, etc.

[0053] The display panel 110 may include a plurality of pixels, and each pixel may be composed of a plurality of sub-pixels. For example, each pixel may be composed of three sub-pixels corresponding to a plurality of lights (e.g., lights of red, green, and blue (R, G, B)). However, the present disclosure is not limited thereto, and depending on the situation, in addition to red, green, and blue sub-pixels, cyan, magenta, yellow, and black or sub-pixels of other colors may be included. Here, the display panel 110 may be implemented as a quantum dot light emitting diode (QLED) panel, a liquid crystal display (LCD), etc. However, the display panel 110 can be implemented in different forms only when backlight dimming can be applied.

[0054] The backlight unit 120 irradiates light to the display panel 110.

[0055] Specifically, the backlight unit 120 irradiates light to the display panel 110 on the rear surface of the display panel 110 (on the opposite surface of the surface on which the image is displayed).

[0056] The backlight unit 120 may include a plurality of light sources, and the plurality of light sources may include a linear light source such as a lamp and a point light source such as a light emitting diode, etc., but is not limited thereto. The backlight unit 120 may be implemented as a direct - type backlight unit or an edge - type backlight unit. The light source of the backlight unit 120 may include any one or two or more types of light sources among light emitting diodes (LEDs), hot cathode fluorescent lamps (HCFLs), cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs), ELP, and FFL.

[0057] According to an embodiment, the backlight unit 120 may be implemented as a plurality of LED modules and / or a plurality of LED cabinets. In addition, the LED module may include a plurality of LED pixels, and according to an embodiment, the LED pixel may be implemented as a blue LED or a white LED, but is not limited thereto, and the LED pixel may be implemented in a form including at least one of a red LED, a green LED, or a blue LED.

[0058] The backlight driver 130 may be implemented in a form including a driver IC for driving the backlight unit 120. For example, in the case where the light source included in the backlight unit 120 is implemented as an LED element, the driver IC may be implemented as at least one LED driver for controlling the current applied to the LED element. According to an embodiment, the LED driver may be arranged at the backend of a power supply (e.g., a switch - mode power supply (SMPS)) and receive voltage from the power supply. However, according to another embodiment, the LED driver may receive voltage from a separate power device. In an embodiment, it is possible that the LED driver is implemented in the form of a module in which the SMPS and the LED driver are integrated into one.

[0059] At least one processor 140 controls the overall operation of the display device 100. Specifically, at least one processor 140 may be connected to each component of the display device 100 and control the overall operation of the display device 100. For example, at least one processor 140 may be electrically connected to the display panel 110, the backlight unit 120, and the backlight driver 130 and control the overall operation of the display device 100. The processor 140 may be composed of one or more processors.

[0060] At least one processor 140 may perform the operation of the display device 100 according to an embodiment by executing at least one instruction stored in the memory.

[0061] At least one processor 140 may include one or more of a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), an integrated many-core (MIC), a digital signal processor (DSP), a neural processing unit (NPU), a hardware accelerator, or a machine learning accelerator. At least one processor 140 may control one or a random combination of other components of the display device, and perform operations regarding communication or data processing. At least one processor 140 may execute one or more programs or instructions stored in the memory. For example, at least one processor 140 may execute the method according to an embodiment by executing one or more instructions stored in the memory.

[0062] In the case where the method according to an embodiment includes multiple operations, the multiple operations may be executed by one processor, or by multiple processors. For example, when a first operation, a second operation, and a third operation are executed by the method, all of the first operation, the second operation, and the third operation may be executed by a first processor, or the first operation and the second operation may be executed by a first processor (e.g., a general-purpose processor), and the third operation may be executed by a second processor (e.g., an artificial intelligence dedicated processor).

[0063] In addition, at least one processor 140 may be implemented as a single-core processor including one core, or it may be implemented as one or more multi-core processors including multiple cores (e.g., the same type of multi-core or different types of multi-cores). In the case where at least one processor 140 is implemented as a multi-core processor, each of the multiple cores included in the multi-core processor may include an internal memory of the processor, such as a cache memory, an on-chip memory, etc., and a common cache shared by the multiple cores may be included in the multi-core processor. In addition, each of the multiple cores (or some of the multiple cores) included in the multi-core processor may independently read the program instructions for implementing the method and execute the instructions, or multiple entire cores (or some cores) may be linked to each other, and read the program instructions for implementing the method and execute the instructions.

[0064] In the case where the method according to an embodiment includes multiple operations, the multiple operations may be executed by one of the multiple cores included in the multi-core processor, or they may be implemented by multiple cores. For example, when a first operation, a second operation, and a third operation are executed by the method, all of the first operation, the second operation, and the third operation may be executed by the first core included in the multi-core processor, or the first operation and the second operation may be executed by the first core included in the multi-core processor, and the third operation may be executed by the second core included in the multi-core processor.

[0065] According to an embodiment, the processor may refer to a system-on-chip (SoC) in which at least one processor and other electronic components are integrated, a single-core processor, a multi-core processor, or a core included in a single-core processor or a multi-core processor. In addition, the core may be implemented as a CPU, GPU, APU, MIC, DSP, NPU, hardware accelerator, or machine learning accelerator, etc., but the embodiments of the present disclosure are not limited thereto. Hereinafter, for ease of explanation, at least one processor 140 will be referred to as processor 140.

[0066] Figure 3 is a diagram showing a display driving method according to one or more embodiments of the present disclosure.

[0067] Referring to Figure 3 , in operation S310, the processor 140 may identify the output frequency (first frequency) of the synchronization signal that varies according to the variable refresh rate of the image. Here, the image may be a variable-frequency image (e.g., an image with a variable frame rate), and the synchronization signal may be a vertical synchronization (Vsync) signal (e.g., a reference signal for refreshing the image). That is, the processor 140 may identify the first frequency as the variable frequency of the output synchronization signal, where the first frequency varies based on the variable frequency (variable frame rate) of the image.

[0068] In operation S320, the processor 140 may output a synchronization signal to the backlight driver 130 at a frequency (second frequency) higher than the identified output frequency of the synchronization signal according to predetermined information. That is, the processor 140 may output the synchronization signal at a second frequency higher than the first frequency.

[0069] In operation S330, the backlight driver 130 may drive the backlight unit 120 by identifying a dimming section based on the received synchronization signal according to the variable refresh rate.

[0070] Here, the predetermined information may include information for identifying a synchronization signal and information for identifying a variable frequency of an image (e.g., a variable frame rate of the image) based on the variable frequency of the synchronization signal received at the backlight driver 130. For example, when the predetermined information is two times, if the output frequency of the synchronization signal is 60 Hz, the processor 140 may output a synchronization signal to the backlight driver 130 at a frequency of 120 Hz. In this case, if the synchronization signal is received at intervals of 1 / 120 seconds, the backlight driver 130 may recognize only the synchronization signal received at intervals of 1 / 60 seconds as a timing signal for backlight dimming and recognize the synchronization signals received at different time points as synchronization signals for identifying sections of the backlight unit according to the variable refresh rate. That is, the backlight driver 130 knows in advance that the synchronization signal is received at twice the refresh rate of the image signal, and if the synchronization signal is received at intervals of 1 / 120 seconds, the backlight driver 130 may recognize that the refresh rate of the image signal is 60 Hz and identify the backlight dimming section based on it. Therefore, even if the refresh rate of the image changes, the variable refresh rate of the image can be predicted before the synchronization signal for the next backlight dimming is received, and thus the refresh rate can be appropriately responded to.

[0071] Figure 4 is a diagram illustrating a display driving method according to one or more embodiments of the present disclosure.

[0072] Reference Figure 4 In operation S410, if a variable frequency image is input, the processor 140 may identify the output frequency of the synchronization signal that changes according to the variable refresh rate of the variable frequency image. That is, the processor 140 may identify the variable output frequency that changes based on the variable refresh rate of the image. Here, the synchronization signal may be a Vsync signal.

[0073] In operation S420, the processor 140 may output a synchronization signal to the backlight driver 130 at a frequency corresponding to a multiple (e.g., n times) of the output frequency of the identified synchronization signal based on the predetermined information. Here, the predetermined information may be information set such that the synchronization signal is output at a frequency corresponding to n times the output frequency of the synchronization signal identified based on the input image. Here, the value of n may be a value predefined as a number greater than 1 (a value set at the time of manufacture or a value set by the user). For example, the value of n may be an integer of 2 or greater, but is not necessarily limited thereto. According to an embodiment, when the variable frequency image is output at a frame rate of 60 Hz and the value of n is set to 2, the processor 140 may output the synchronization signal at 120 Hz.

[0074] In operation S430, the backlight driver 130 may drive the backlight unit 120 by identifying a dimming section according to a variable refresh rate based on predetermined information and a reception point of a synchronization signal. Here, the dimming section may mean a period during which the backlight is turned on in one frame section.

[0075] According to an embodiment, the backlight driver 130 may identify a first synchronization signal in the synchronization signal received from the processor 140 as a timing signal (e.g., power cycle) for turning on or off the backlight unit 120 based on predetermined information. In addition, the backlight driver 130 may identify a dimming section (or effective dimming time) of the backlight unit 120 according to a variable refresh rate based on the first synchronization signal and a second synchronization signal received at a time point different from the first synchronization signal. This is because the second synchronization signal is a signal received when the synchronization signal is output at a frequency corresponding to n times the output frequency of the synchronization signal identified based on an input image. That is, the second synchronization signal is a signal for the backlight driver 130 to identify a dimming section according to a variable refresh rate, rather than a timing signal for actually turning on or off the backlight unit 120.

[0076] For example, the backlight driver 130 may identify a variable frequency of an image according to a variable refresh rate based on a time that is n times a time interval between receiving the first synchronization signal and the second synchronization signal. For example, when the time interval between receiving the first synchronization signal and the second synchronization signal is 1 / 120 second, the backlight driver 130 may multiply 1 / 120 by n times included in the predetermined information and identify an actual refresh rate of the input image. For example, when the n value is set to 2, the backlight driver 130 may identify the variable frequency of the image as 1 / 120 second * 2 = 1 / 60 second (e.g., 60 Hz). In this case, even if the refresh rate of the image continuously changes, the changed refresh rate can be immediately identified, and a backlight dimming section can be set based thereon.

[0077] Figure 5 is a diagram illustrating a display driving method according to one or more embodiments of the present disclosure.

[0078] Refer to Figure 5 , if a variable frequency image is input, the processor 140 may identify an output frequency of a synchronization signal that changes according to a variable refresh rate of the variable frequency image in operation S510. Here, the synchronization signal may be a Vsync signal.

[0079] In operation S520, the processor 140 may output a synchronization signal to the backlight driver 130 at a frequency corresponding to twice the output frequency of the recognized synchronization signal based on predetermined information. Here, the predetermined information may be information set such that the synchronization signal is output at a frequency corresponding to twice the output frequency of the synchronization signal recognized based on the input image.

[0080] In this case, in operation S530, the backlight driver 130 may identify the variable frequency of the image according to the variable refresh rate based on twice the time interval between receiving the first synchronization signal and the second synchronization signal consecutive to the first synchronization signal.

[0081] Then, the backlight driver 130 may identify the dimming section of the backlight unit 120 based on the variable frequency of the recognized image and drive the backlight unit 120. For example, when the time interval between receiving the first synchronization signal and the second synchronization signal is 1 / 120 second, the backlight driver 130 may multiply 1 / 120 by twice included in the predetermined information and identify the actual refresh rate of the input image as 60 Hz. In this case, even if the refresh rate of the image changes continuously, the changed refresh rate can be immediately recognized, and the backlight dimming section can be set based on it.

[0082] Figure 6 is a diagram showing a method of identifying a backlight dimming section based on a synchronization signal according to an embodiment.

[0083] Reference Figure 6 , the refresh rate of the image changes in a sequence including 120 Hz, 180 Hz, 150 Hz, 130 Hz, and 100 Hz.

[0084] In this case, the first Vsync signal (611 - 619) for controlling the on / off of the backlight unit 120 based on the refresh rate of the image is recognized as 1 / 120 second in interval 630, 1 / 180 second in interval 640, 1 / 150 second in interval 650, 1 / 130 second in interval 660, and 1 / 100 second in interval 670. However, according to an embodiment, when the Vsync signal is output at twice the refresh rate of the image, a second Vsync signal (621 - 629) may be additionally output in the first Vsync signal (611 - 619). In this case, the backlight driver 130 may predict the refresh rate of the image that changes based on the intervals between the first Vsync signal (611 - 619) and the second Vsync signal (621 - 629), and set the backlight dimming section based on it. Therefore, a motion blur reduction function can be achieved, thereby minimizing the increase / decrease in brightness even when the refresh rate of the image changes.

[0085] Figure 7A andFigure 7B is a diagram showing a method of identifying the dimming duty ratio of each backlight block during local dimming according to an embodiment.

[0086] Refer to Figure 7A and Figure 7B , if a variable refresh rate of an image is identified, the processor 140 may identify a backlight dimming section based on the identified refresh rate (e.g., the display time of an image frame) and the pixel information of the image frame.

[0087] In the case where the backlight unit is implemented as the edge-type backlight unit 120-2, the processor 140 may obtain the pixel information (e.g., APL information) of each image area to be displayed in the screen area corresponding to each backlight block, and calculate the dimming duty ratio of the backlight block corresponding to the screen area based on the obtained pixel information.

[0088] For example, as Figure 7A shown on the right side of, the processor 140 may calculate the APL information of the image areas 111-1 to 111-n corresponding to each backlight block 121-1 to 121-n. For example, Figure 7B the left side of shows the case of calculating the APL values 711-1 to 711-n of each image area 111-1 to 111-n.

[0089] As Figure 7B shown, the processor 140 may calculate the dimming duty ratios 721-1 to 721-n of each backlight block 121-1 to 121-n corresponding to each screen area based on the APL values of each image area obtained in Figure 7A . For example, the dimming duty ratio of each backlight block 121-1 to 121-n may be calculated by applying a predetermined weight to the APL value of each image area. For example, the dimming duty ratio of an image area where the APL is 10% may be calculated as 10% * 6 = 60%, and the dimming duty ratio of an image area where the APL is 7% may be calculated as 7% * 6 = 42%. However, this is only an example of calculating the dimming duty ratio, and the dimming duty ratio may be calculated based on the pixel information of each screen area by various methods. When calculating the dimming duty ratio as described above, the processor 140 may multiply the display time of the image frame by the dimming duty ratio and identify the backlight dimming section (e.g., the backlight on / off time) in each frame section.

[0090] According to an embodiment, global dimming can be used for motion blur reduction (MBR). In this case, instead of separately calculating the dimming duty ratio of each backlight block 121-1 to 121-n, the dimming duty ratio to be applied to each backlight block 121-1 to 121-n as a whole can be calculated based on the pixel information of the entire image to be displayed. For example, the dimming duty ratio of the backlight block corresponding to the entire screen area can be calculated based on the APL information corresponding to the entire image to be displayed. In an embodiment, overall dimming control can be performed for each backlight block 121-1 to 121-n based on a representative value (e.g., average value) of the dimming duty ratio separately calculated for each backlight block 121-1 to 121-n.

[0091] Figure 8 and Figure 9 are diagrams showing a display driving method according to one or more embodiments of the present disclosure.

[0092] Refer to Figure 8 , in operation S810, if a variable frequency image is input, the processor 140 may identify the output frequency of the synchronization signal that changes according to the variable refresh rate of the variable frequency image. Here, the synchronization signal may be a Vsync signal.

[0093] In operation S820, if the output frequency of the identified synchronization signal is the first output frequency, then in operation S830, the processor 140 may output the synchronization signal to the backlight driver 130 at a frequency corresponding to n1 times the first output frequency.

[0094] In operation S820, if the output frequency of the identified synchronization signal is not the first output frequency, and in operation S840, if the output frequency of the identified synchronization signal is the second output frequency, then in operation S850, the processor 140 may output the synchronization signal to the backlight driver 130 at a frequency corresponding to n2 times the second output frequency. Here, n1 and n2 may be different values, and they may be, for example, different integers.

[0095] In operation S860, the backlight driver 130 may identify the dimming section of the backlight unit 120 according to the variable refresh rate based on the predetermined information and the reception point of the synchronization signal.

[0096] According to an embodiment, the n value may be set to be inversely proportional to the output frequency. For example, in the case where the first output frequency is less than the second output frequency, the n1 value may be greater than the n2 value. For example, as Figure 9As shown, if the first output frequency is 120 Hz and the second output frequency is 180 Hz, the value of n1 corresponding to the first output frequency can be 3, and the value of n2 corresponding to the second output frequency can be 2. Therefore, in the case where the output frequency of the synchronization signal recognized according to the refresh rate is 120 Hz and the output frequency is 180 Hz, the synchronization signal can be output to the backlight driver 130 at 360 Hz. As described above, the n value can be adjusted to be inversely proportional to the output frequency of the synchronization signal recognized according to the refresh rate. However, in this case, information related to n1 and / or n2 should be included in the synchronization signal corresponding to the on / off timing of the backlight. For example, the processor 140 can provide information about the n value that changes by adjusting the pulse intensity of the Vsync signal to the backlight driver 130. In this case, the backlight driver 130 can identify the n value based on the pulse intensity of the Vsync signal and identify the variable refresh rate based on it.

[0097] Figure 10 is a diagram illustrating a display driving method according to one or more embodiments of the present disclosure.

[0098] Refer to Figure 10 , in operation S1010, the processor 140 can identify the n value based on at least one of the minimum value, maximum value, intermediate value, or average value of the variable refresh rate. According to an embodiment, it is also possible that the n value is determined based on the characteristics of the panel or information about the image. For example, the processor 140 can identify the n value based on the available VRR range of the display panel 110, or identify the n value based on information about the variable frequency image (e.g., metadata). According to an embodiment, the processor 140 can set the n value to the a value when the available VRR range of the display panel 110 is the first range, and set the n value to the b value when the available VRR range of the display panel 110 is the second range. For example, when the available VRR range is relatively wider, the processor 140 can set the n value to a relatively larger value, but the present disclosure is not limited thereto.

[0099] In operation S1020, the processor 140 can output a synchronization signal to the backlight driver 130 at a frequency corresponding to n times the output frequency of the synchronization signal.

[0100] In operation S1030, the backlight driver 130 can identify the dimming section of the backlight unit according to the variable refresh rate based on the reception point of the synchronization signal.

[0101] Figure 11 , Figure 12A , Figure 12B and Figure 12C is a diagram illustrating a display driving method according to one or more embodiments of the present disclosure.

[0102] Reference Figure 10 In operation S1110, the processor 140 may identify the n value based on the luminance information of the variable-frequency image.

[0103] According to an embodiment, the processor 140 may identify the n value based on the average luminance information of the variable-frequency image. For example, when the luminance information of the variable-frequency image is low, the dimming section of the backlight within the first frame may become shorter, so the variable frequency of the variable-frequency image should be identified relatively faster, and thus, the processor 140 may set the n value to a relatively larger value. In an embodiment, when it is possible to identify the luminance information of a specific frame section (e.g., each scene section), the processor 140 may identify the n value based on the average luminance information of each scene section. In an embodiment, when it is possible to identify the minimum luminance information of the variable-frequency image and / or the minimum luminance information of each scene part, the processor 140 may differently set the n value based on whether the minimum luminance value is greater than or equal to a threshold.

[0104] In operation S1120, the processor 140 may output a synchronization signal to the backlight driver 130 at a frequency corresponding to n times the output frequency of the synchronization signal.

[0105] For example, as Figures 12A to 12C shown, the n value may increase as the luminance information of each frame section decreases. For example, in Figure 12A , since the Vsync is output at twice the frame rate of the image based on the first luminance information according to the backlight dimming lengths 1221 and 1222, the second Vsync signal between the first Vsync signals 1211, 1212, and 1213 is output once more. For example, in Figure 12B , since the Vsync is output at three times the frame rate of the image based on the second luminance information according to the backlight dimming lengths 1223 and 1224, the second Vsync signal between the first Vsync signals 1211, 1212, and 1213 is output twice more. For example, in Figure 12C , since the Vsync signal is output at four times the frame rate of the image based on the second luminance information according to the backlight dimming lengths 1225 and 1225, the second Vsync signal between the first Vsync signals 1211, 1212, and 1213 is output three more times.

[0106] Figure 13 is a diagram showing a detailed configuration of a display device according to one or more embodiments of the present disclosure.

[0107] Reference Figure 13 , the display device 100' may include a display panel 110, a backlight unit 120, a backlight driver 130, at least one processor 140, a panel driver 150, a memory 160, a communication interface 170, and a user interface 180. Among the Figure 13 components shown, regarding the components that overlap with the Figure 2 components shown in, the detailed description thereof will be omitted.

[0108] The panel driver 150 may be implemented in a form including a driver IC for driving the display panel 110. According to an embodiment, the driver IC (e.g., a timing controller (TCON)) may be implemented as hardware separate from the processor 140. For example, the panel driver 150 may include a data driver that provides video data to data lines, and a gate driver that provides scan pulses to gate lines.

[0109] The data driver is a device for generating data signals, and it receives image data of R / G / B components from the processor 140 and generates data signals. In addition, the data driver is connected to the data lines DL1, DL2, DL3,..., DLm of the display panel 110, and applies the generated data signals to the display panel 110.

[0110] The gate driver (or scan driver) is a device for generating gate signals (or scan signals), and it is connected to the gate lines GL1, GL2, GL3,..., GLn, and transmits the gate signals to a specific row of the display panel 110. The data signals output from the data driver are transmitted to the pixels to which the gate signals are transmitted.

[0111] The memory 160 may store data required for various embodiments. Depending on the use of the stored data, the memory 160 may be implemented in the form of a memory embedded in the display device 100', or in the form of a memory that can be attached to or detached from the display device 100'. For example, in the case of data for operating the display device 100', the data may be stored in a memory embedded in the display device 100', and in the case of data for the extended functions of the display device 100', the data may be stored in a memory that can be attached to or detached from the display device 100'. According to an embodiment, in the case of a memory embedded in the display device 100', the memory may be implemented as at least one of a volatile memory (e.g., dynamic RAM (DRAM), static RAM (SRAM), or synchronous dynamic RAM (SDRAM), etc.) or a non-volatile memory (e.g., one-time programmable ROM (OTPROM), programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), mask ROM, flash ROM, flash memory (e.g., NAND flash or NOR flash, etc.), hard disk drive, or solid state drive (SSD)). In addition, in the case of a memory that can be attached to or detached from the display device 100', the memory may be implemented in the form of, for example, a memory card (e.g., compact flash (CF), secure digital (SD), micro secure digital (Micro-SD), mini secure digital (Mini-SD), extreme digital (xD), multimedia card (MMC), etc.), an external memory that can be connected to a USB port (e.g., USB memory), etc.

[0112] According to an implementation example of the display device 100', the communication interface 170 may be implemented as various interfaces. For example, the communication interface 170 may receive an input of an image signal from an external device, an external storage medium (e.g., USB memory), an external server (e.g., webhard), etc. through a communication method such as Bluetooth, AP-based Wi-Fi (Wi-Fi, wireless LAN network), Zigbee, wired / wireless local area network (LAN), wide area network (WAN), Ethernet, IEEE 1394, high-definition multimedia interface (HDMI), universal serial bus (USB), mobile high-definition link (MHL), AES / EBU (Audio Engineering Society / European Broadcasting Union), optical, coaxial, etc., by a streaming or downloading method. Here, the input image may be any one of standard definition (SD), high definition (HD), full HD, or ultra HD digital images, but is not limited thereto.

[0113] The user interface 180 may be implemented as a device such as a button, a touchpad, a mouse, and a keyboard, or may be implemented as a touch screen or the like that can perform the foregoing display function and manipulation input function together.

[0114] In addition to the above, according to an implementation example, the display device 100' may include a speaker, a camera, a microphone, a tuner, a demodulator, and the like.

[0115] The speaker may be a component that outputs not only various audio data but also various notification sounds or voice messages, etc.

[0116] The camera may be turned on according to a predetermined event and perform shooting.

[0117] The microphone is a component for receiving the input of the user's voice or other sounds and converting them into audio data. According to an embodiment, according to another embodiment, the display device 100' may receive the user's voice input through an external device via the communication interface 170.

[0118] The tuner may tune to the channel selected by the user in the radio frequency (RF) broadcast signal received through the antenna, or all the pre-stored channels, and receive the RF broadcast signal.

[0119] The demodulator may receive the digital intermediate frequency (DIF) signal converted at the tuner and demodulate the signal, and perform channel demodulation and the like.

[0120] According to the foregoing various embodiments, a motion blur reduction function may be implemented, through which even if the refresh rate of the image changes, the increase / decrease in brightness is minimized.

[0121] The methods according to the foregoing various embodiments of the present disclosure may be implemented in the form of an application that can be installed on a conventional display device. In an embodiment, the methods according to the foregoing various embodiments of the present disclosure may be performed by using a deep learning-based artificial neural network (or deep artificial neural network) (for example, a learning network model). According to an embodiment, image processing may be performed by a trained neural network model.

[0122] In addition, the methods according to the foregoing various embodiments of the present disclosure may be implemented only by software upgrade or hardware upgrade of a conventional display device.

[0123] In addition, the methods according to the foregoing various embodiments of the present disclosure may be performed by providing an embedded server on the display device or an external server of the display device.

[0124] The foregoing various embodiments may be implemented as software including instructions stored in a machine-readable storage medium, which can be read by a machine (e.g., a computer). A machine refers to a device that invokes instructions stored in a storage medium and can operate according to the invoked instructions, and the device may include a display device (e.g., Display Device A) according to the foregoing embodiments. In the case where the instructions are executed by a processor, the processor may execute the functions corresponding to the instructions by itself or by using other components under its control. The instructions may include code generated or executed by a compiler or an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory" only means that the storage medium does not include signals and is tangible, but does not indicate whether the data is stored in the storage medium semi-permanently or temporarily.

[0125] In addition, a method according to the foregoing various embodiments may be provided while being included in a computer program product. A computer program product refers to a product, and it can be traded between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., a Compact Disc Read-Only Memory (CD-ROM)), or may be distributed online through an application store (e.g., Play Store TM ). In the case of online distribution, at least a part of the computer program product may be at least temporarily stored in a storage medium such as a memory of a manufacturer's server, an application store's server, and a relay server, or may be temporarily generated.

[0126] In addition, each of the components (e.g., modules or programs) according to the foregoing various embodiments may be composed of a single object or multiple objects. In addition, in the corresponding sub-components described above, some sub-components may be omitted, or other sub-components may be further included in various embodiments. In an embodiment, some components (e.g., modules or programs) may be integrated into an object, and the functions performed by each component before integration are the same or similar. In addition, the operations performed by a module, a program, or other components according to an embodiment may be executed sequentially, in parallel, repeatedly, or heuristically. Alternatively, at least some of the operations may be executed in a different order or omitted, or other operations may be added.

[0127] In addition, although example embodiments of the present disclosure have been shown and described, the present disclosure is not limited to the above specific embodiments, and it is clear that various modifications can be made by those of ordinary skill in the art to which the present disclosure pertains without departing from the gist of the present disclosure protected by the appended claims and their equivalents. In addition, such modifications are not intended to be interpreted independently of the technical concept or prospect of the present disclosure.

Claims

1. A display device, comprising: A display panel; A backlight unit configured to output light; A backlight driver configured to drive the backlight unit; A memory storing at least one instruction; And At least one processor operably connected to the display panel, the backlight unit, the backlight driver, and the memory, Wherein the at least one processor is configured to execute the at least one instruction to: Identify a first output frequency of a synchronization signal that varies based on the variable refresh rate of the image, Based on predetermined information, output the synchronization signal to the backlight driver at a second output frequency, the second output frequency being a frequency higher than the first output frequency, Wherein the backlight driver is further configured to: drive the backlight unit by identifying a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on receiving the synchronization signal at the second output frequency.

2. The display device according to claim 1, wherein The predetermined information includes information for identifying the synchronization signal and the variable frequency of the image based on the variable frequency among a plurality of synchronization signals received at the backlight driver.

3. The display device according to claim 1, wherein, The at least one processor is further configured to execute the at least one instruction to: Based on the predetermined information, output the synchronization signal to the backlight driver at a frequency corresponding to n times the first output frequency, where n is a positive integer, Wherein the backlight driver is configured to drive the backlight unit by identifying a dimming section corresponding to the variable refresh rate of the image based on the predetermined information and the reception point of the synchronization signal.

4. The display device according to claim 3, wherein, The backlight driver is further configured to: Based on the predetermined information, identify a first synchronization signal among a plurality of synchronization signals received from the at least one processor as a timing signal for power cycling the backlight unit; And Based on the first synchronization signal and a second synchronization signal received at a time point different from the first synchronization signal, identify the dimming section of the backlight unit corresponding to the variable refresh rate of the image.

5. The display device according to claim 3, wherein, The backlight driver is further configured to: Based on the time interval between receiving the first synchronization signal and the second synchronization signal, identify the variable frequency of the image corresponding to the variable refresh rate of the image; And Based on the variable frequency of the image, identify the dimming section of the backlight unit.

6. The display device according to claim 3, wherein, The at least one processor is further configured to execute the at least one instruction to: Identify the n value based on at least one of a minimum value, a maximum value, a median value, or an average value of the variable refresh rate of the image.

7. The display device according to claim 1, wherein, The at least one processor is further configured to execute the at least one instruction to: Identify the n value based on the luminance information of the image.

8. The display device according to claim 1, wherein, The at least one processor is further configured to execute the at least one instruction to: Based on the predetermined information, output the synchronization signal to the backlight driver at the second output frequency, the second frequency corresponding to n times the first output frequency, where n is 2, Wherein the backlight driver is further configured to: Based on the time interval between the first synchronization signal and the second synchronization signal consecutive to the first synchronization signal with n being 2, identify the variable frequency of the image corresponding to the variable refresh rate of the image; and Identify the dimming section of the backlight unit based on the variable frequency of the image.

9. The display device according to claim 1, wherein The at least one processor is further configured to execute the at least one instruction to: Based on the first output frequency having a first frequency value, output the synchronization signal to the backlight driver at a frequency corresponding to a first multiple n1 of the first frequency value; And Based on the first output frequency having a second frequency value, output the synchronization signal to the backlight driver at a frequency corresponding to a second multiple n2 of the second frequency value, where n1 and n2 are different integers.

10. The display device according to claim 1, wherein, The at least one processor is further configured to execute the at least one instruction to: Change the current applied in the dimming section of the backlight unit to compensate for the change in the brightness of the image corresponding to the variable refresh rate.

11. A method for driving a display device, the method comprising: Identify a first output frequency of a synchronization signal that varies based on a variable refresh rate of an image; Based on predetermined information, output the synchronization signal to a backlight driver at a second output frequency that is a higher frequency than the first output frequency; And Drive the backlight unit by identifying a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on receiving the synchronization signal at the backlight driver.

12. The method according to claim 11, Among them, The predetermined information includes: Information for identifying the synchronization signal and the variable frequency of the image based on the variable frequency among a plurality of synchronization signals received at the backlight driver.

13. The method according to claim 11, wherein, Outputting the synchronization signal to the backlight driver at the second output frequency includes: Based on the predetermined information, output the synchronization signal to the backlight driver at a frequency corresponding to an n - fold of the first output frequency, where n is a positive integer; and Based on the predetermined information and the reception point of the synchronization signal, identify the dimming section of the backlight unit corresponding to the variable refresh rate of the image.

14. The method according to claim 13, wherein, The driving the backlight unit includes: Based on the predetermined information, identify a first synchronization signal among a plurality of synchronization signals received at the backlight driver as a timing signal for power - cycling the backlight unit; and Based on the first synchronization signal and a second synchronization signal received at a time point different from the first synchronization signal, identify the dimming section of the backlight unit corresponding to the variable refresh rate of the image.

15. A non - transitory computer - readable medium for storing computer - readable program code or instructions that can be executed by a processor to perform a method for driving a display device, the method comprising: Identify a first output frequency of a synchronization signal that varies based on a variable refresh rate of an image; Output the synchronization signal to the backlight driver at a second output frequency based on predetermined information, where the second output frequency is a frequency higher than the first output frequency; and Drive the backlight unit by identifying a dimming section of the backlight unit corresponding to the variable refresh rate of the image based on receiving the synchronization signal at the backlight driver.

Images