KR102408806B1 - Liquid Display Device And Method Of Driving The Same - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of improving display quality by driving Boost Peak Luminance (BPL) and Smart Black, and a driving method thereof.
The liquid crystal display device of the present invention includes a liquid crystal panel in which a plurality of sub-pixels are disposed, a plurality of light emitting diode (LED) arrays and a driving circuit unit disposed under the liquid crystal panel. The driving circuit unit includes a timing controller, a dimming control unit, and an LED driver. The timing controller generates a dimming signal of the plurality of LED arrays by analyzing the input image signal. In addition, the dimming control unit analyzes the dimming signal and sets the size of the first LED array block that emits light with a peak luminance according to an image pattern. In addition, the dimming control unit sets a minimum duty value of the second LED array block that emits light with a low luminance. And, the dimming data including the size value of the first LED array block and the minimum duty value of the second LED array block is generated. And, the LED driver drives the plurality of LED arrays according to the dimming data.

Description

Liquid Display Device And Method Of Driving The Same

The present invention relates to a liquid crystal display device, and to a liquid crystal display device capable of improving display quality by adjusting the peak luminance of an LED (light emitting diode) array according to an image pattern, and a driving method thereof.

An active matrix type liquid crystal display device displays an image by controlling the light transmittance of the liquid crystal through a thin film transistor (TFT), which is a switching element. Such liquid crystal display devices are being applied to portable information devices, office devices, computers, and IT products due to their advantages such as light weight, thin shape, and low power consumption driving, and their application ranges are widening.

Since the liquid crystal display device is not a self-luminous device, an image is displayed using light supplied through a backlight unit provided under the liquid crystal panel. When the transmittance of light transmitted through the liquid crystal layer of the liquid crystal panel is increased to the maximum, the liquid crystal panel realizes a white image with high luminance. Conversely, when the light transmittance of the liquid crystal layer is reduced to a minimum, the liquid crystal panel realizes a black image with low luminance.

In the conventional liquid crystal display device, the backlight unit irradiates light with maximum luminance, and the liquid crystal panel displays an image by adjusting the amount of light transmitted from the backlight unit according to the electric field applied to the unit cell unit. Accordingly, the amount of light transmission of the liquid crystal cell is changed according to the image data supplied to each sub-pixel, and the luminance of the image displayed on the liquid crystal panel is changed according to the amount of light transmission.

1 is a view showing a plurality of LED arrays disposed in a backlight unit of a liquid crystal display device according to the prior art. 1 illustrates a plurality of light emitting diode (LED) arrays among the configurations of the backlight unit, and optical members (diffuser plates and optical sheets) are not illustrated.

Referring to FIG. 1 , a plurality of LED arrays 10 (eg, 80 LED arrays) are disposed in a backlight unit 1 , and a plurality of LEDs 12 are disposed in each LED array 10 . . As the importance of low power consumption and DCR (Dynamic Contrast Ratio) increases, global dimming and local dimming methods that link the brightness of image data and backlight Interest in the same dynamic driving method is growing. The global dimming method drives the plurality of LED arrays 10 with the same dimming value. On the other hand, the local dimming method drives each of the plurality of LED arrays 10 with individual dimming values.

Recently, a demand for a liquid crystal display device to which a high dynamic range (HDR) technology capable of realizing high image quality is applied is increasing. HDR technology improves the display quality by increasing the contrast ratio between the bright screen and the dark screen, which makes the brightness of the LED array corresponding to the bright image 1.5 times brighter than the normal mode.

However, when HDR technology is applied, there is a problem in that light from a high luminance region enters a low luminance region and light leakage increases. In particular, there is a problem in that the difference between the light leakage area and the light leakage degree increases according to the duty value of the peak luminance area, thereby degrading display quality. In addition, since the liquid crystal display device of the prior art applies HDR technology without considering the pattern of the image (eg, aspect ratio), the deviation of light leakage according to the pattern of the image is different, so uniform display quality cannot be guaranteed. There is this.

The inventors of the present application recognized the above-mentioned problems and presented the following technical problems.

An object of the present invention is to provide a liquid crystal display device capable of reducing light leakage during high dynamic range (HDR) driving and a driving method thereof to solve the problems described above.

The present invention is to solve the problems described above, and to provide a liquid crystal display device capable of setting the size of an LED array block that emits light with a peak luminance according to an image pattern (eg, aspect ratio) and a driving method thereof make it a technical task.

The present invention is to solve the above-described problems, and a liquid crystal display device capable of adjusting the minimum duty value of an LED array block that emits light with low luminance according to an image pattern (eg, an aspect ratio) and driving the same It is a technical task to provide a method.

The present invention is to solve the problems described above, and a liquid crystal display device capable of adjusting the minimum duty value of an LED array block disposed between an LED array block emitting light with a peak luminance and an LED array block emitting light with a low luminance, and driving the same It is a technical task to provide a method.

In addition to the technical problems of the present invention mentioned above, other features and advantages of the present invention will be described below, or will be clearly understood by those of ordinary skill in the art from such description and description.

In order to achieve the above-described technical problem, a liquid crystal display device of the present invention includes a liquid crystal panel in which a plurality of sub-pixels are disposed, a plurality of light emitting diode (LED) arrays and a driving circuit unit disposed under the liquid crystal panel. . The driving circuit unit includes a timing controller, a dimming control unit, and an LED driver. The timing controller generates a dimming signal of the plurality of LED arrays by analyzing the input image signal. In addition, the dimming control unit analyzes the dimming signal and sets the size of the first LED array block that emits light with a peak luminance according to an image pattern. In addition, the dimming control unit sets a minimum duty value of the second LED array block that emits light with a low luminance. And, the dimming data including the size value of the first LED array block and the minimum duty value of the second LED array block is generated. And, the LED driver drives the plurality of LED arrays according to the dimming data.

In order to achieve the above-described technical problem, a method of driving a liquid crystal display device of the present invention generates a dimming signal of a plurality of LED arrays by analyzing an input image signal. Thereafter, the dimming signal is analyzed to set a size value of the first LED array block that emits light with a peak luminance according to an image pattern. Then, a minimum duty value of the second LED array block that emits light with a low luminance is set. Thereafter, dimming data including a size value of the first LED array block and a minimum duty value of the second LED array block is generated. Then, the plurality of LED arrays are driven according to the dimming data.

The liquid crystal display device and the driving method thereof of the present invention can reduce light leakage during high dynamic range (HDR) driving by setting the size of an LED array block that emits light with peak luminance according to an image pattern (eg, aspect ratio). .

The liquid crystal display device of the present invention and its driving method control the minimum duty value of an LED array block that emits light at low luminance according to an image pattern (eg, an aspect ratio) when driving HDR (High Dynamic Range) It can reduce light leakage.

The liquid crystal display device and the driving method thereof of the present invention control the minimum duty value of the LED array block disposed between the LED array block emitting light with a peak luminance and the LED array block emitting light with a low luminance when driving HDR (High Dynamic Range). It can reduce light leakage.

In addition, other features and advantages of the present invention may be newly recognized through embodiments of the present invention.

1 is a view showing a plurality of LED arrays disposed in a backlight unit of a liquid crystal display device according to the prior art.
2 is a diagram illustrating a liquid crystal display device according to an embodiment of the present invention.
3 is a diagram illustrating a plurality of LED arrays disposed in a backlight unit of a liquid crystal display device according to an embodiment of the present invention.
4 is a diagram illustrating a dimming control unit 170 according to an embodiment of the present invention.
5 is a diagram illustrating a method of driving a liquid crystal display according to an embodiment of the present invention applied to a 21:9 aspect ratio.
6 is a diagram illustrating a method of driving a liquid crystal display according to an embodiment of the present invention applied to a 4:3 aspect ratio.
7 is a diagram illustrating adjustment of a minimum duty value according to gray of an image when a horizontal and vertical aspect ratio of an image pattern has an aspect ratio of 2.35:1 and 2.4:1.
8 is a diagram illustrating a luminance and current increase ratio for each size of a white pattern.

Like reference numerals refer to substantially identical elements throughout. In the following description, a detailed description of configurations and functions known in the art and cases not related to the core configuration of the present invention may be omitted. The meaning of the terms described in this specification should be understood as follows.

Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and those of ordinary skill in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention, and the present invention is only defined by the scope of the claims.

In the present specification, it should be noted that, in adding reference numbers to the components of each drawing, the same numbers are provided to the same components as possible even though they are indicated on different drawings.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are exemplary, and thus the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, cases including the plural are included unless otherwise explicitly stated.

In interpreting the components, it is construed as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal relationship is described with 'after', 'following', 'after', 'before', etc. It may include cases that are not continuous unless this is used.

The term 'at least one' should be understood to include all possible combinations of one or more related items. For example, the meaning of 'at least one of the first item, the second item and the third item' means not only the first item, the second item, or the third item respectively, but also two of the first item, the second item and the third item. It means a combination of all items that can be presented from more than one.

Although the first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each embodiment may be independently implemented with respect to each other or implemented together in a related relationship. may be

Liquid crystal display devices have been developed in various ways, such as twisted nematic (TN) mode, VA (vertical alignment) mode, IPS (in plane switching) mode, and fringe field switching (FFS) mode according to a method of controlling the arrangement of liquid crystal layers.

Among them, the TN mode and the VA mode are methods in which a pixel electrode is formed on a lower substrate and a common electrode is formed on an upper substrate (color filter array substrate) to control the arrangement of liquid crystal layers with a vertical electric field.

Meanwhile, in the IPS mode and the FFS mode, a pixel electrode and a common electrode are disposed on a lower substrate to control the arrangement of the liquid crystal layer by a horizontal electric field between the pixel electrode and the common electrode.

In the IPS mode, a horizontal electric field is generated between both electrodes by alternately arranging the pixel electrode and the common electrode in parallel to control the arrangement of the liquid crystal layer. In the FFS mode, the pixel electrode and the common electrode are formed to be spaced apart from each other with an insulating layer interposed therebetween. At this time, one electrode is configured in a plate shape or pattern and the other electrode is configured in a finger shape to control the arrangement of the liquid crystal layer through a fringe field generated between both electrodes. method. In the liquid crystal panel according to an embodiment of the present invention, both a vertical electric field method (TN mode, VA mode) and a horizontal electric field method (IPS mode, FFS mode) may be applied without mode limitation.

Hereinafter, a liquid crystal display device and a driving method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings.

2 is a diagram illustrating a liquid crystal display device according to an embodiment of the present invention.

Referring to FIG. 2 , the liquid crystal display device 100 according to an embodiment of the present invention includes a liquid crystal panel 110 , a backlight unit 150 , and a driving circuit unit.

The driving circuit unit includes a gate driver 120 , a data driver 130 , a timing controller 140 , an LED driver 160 , and a dimming controller 170 . In addition, a power supply unit (not shown) for supplying power to the liquid crystal panel 110 and the driving circuit unit is included. All or a part of the driving circuit unit may be disposed on the liquid crystal panel 110 in a Chip On Glass (COG) or Chip On Flexible Printed Circuit (COF) method. Here, the dimming control unit 170 may be built into the timing controller 140 or may be arranged as a separate configuration. When the dimming controller 170 is built into the timing controller 140 , a delay may be prevented or reduced when calculating a peak luminance value and a minimum duty value according to an image pattern.

The liquid crystal panel 110 is configured by bonding a first substrate (TFT array substrate) and a second substrate (color filter array substrate) to each other with a liquid crystal layer interposed therebetween. The liquid crystal panel 110 includes an active area A/A in which a screen is displayed and a pad area PA in a non-display area. The pad area PA is disposed outside the active area A/A.

RGB color filters are disposed on the second substrate (color filter array substrate) to correspond to each sub-pixel. A black matrix is disposed to define an opening area of each subpixel and prevent color mixing.

A plurality of subpixels are arranged in a matrix form on a first substrate (TFT array substrate), and the plurality of subpixels are defined by a plurality of data lines and a plurality of gate lines crossing each other. . The R, G, and B subpixels are gathered to form one pixel. In each subpixel, a TFT as a switching element, a pixel electrode, a common electrode, and a storage capacitor Cst are disposed. Here, the pixel electrode is formed for each sub-pixel, and the common electrode is formed in units of a plurality of sub-pixels. The pixel electrode and the common electrode are formed of a transparent conductive material such as indium tin oxide (ITO).

In addition, the liquid crystal display device according to the present invention is a TN (Twisted Nematic) mode, IPS (In-Plane Switching) mode, VA (Vertical Alignment) mode, or FSS (Fringe Field Switching) mode in various forms known in the art, such as can be applied. According to such various modes, the configuration of the first substrate and the second substrate may also be variously changed.

3 is a diagram illustrating a plurality of LED arrays disposed in a backlight unit of a liquid crystal display device according to an embodiment of the present invention.

Referring to FIG. 3 , the backlight unit 150 includes a plurality of LED arrays 152 in which LEDs generating light irradiated to the liquid crystal panel 110 are disposed, and a plurality of LED arrays 152 disposed on the plurality of LED arrays 152 to provide light. It may include an optical member (not shown) for guiding the liquid crystal panel 110 in the direction and improving light efficiency. 2 and 3, the optical member is not shown. The optical member includes a diffusion plate for uniformly irradiating light emitted from the plurality of LED arrays 152 over the entire surface of the liquid crystal panel 110, a prism sheet for improving light efficiency by condensing the light emitted from the diffusion plate, and It may include a polarizing sheet for polarizing light.

A plurality of LED arrays 152 are disposed in the backlight unit 150 , and a plurality of LEDs are disposed in each LED array. Two or more LEDs are disposed in the plurality of LED arrays 152 , and each LED is turned on by driving power supplied from a driving power line and a ground line. In FIG. 3 , four LEDs are arranged in one LED array 152 as an example.

In this case, each LED array 152 may be individually driven under the control of the LED driver 160 , or a certain number of LED arrays 152 may be driven in block units. Here, the plurality of LED arrays 152 may be driven in a global dimming method or may be driven in a local dimming method. In the present invention, the LED arrays corresponding to the high luminance image are configured as a white pattern block 154 (first LED array block), and the size of the white pattern block 154 (first LED array block) is adjusted according to the pattern of the image. do. Specific details thereof will be described with reference to FIGS. 4 to 6 .

The timing controller 140 generates a gate control signal (GCS) for controlling the gate driver 120 using the timing signal TS and supplies it to the gate driver 120 . The gate control signal GCS may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable (GOE).

In addition, the timing controller generates a data control signal (DCS) for controlling the data driver 130 using the timing signal TS and supplies it to the data driver 130 . The data control signal (DCS) is a source start pulse (SSP: Source Start Pulse), a source sampling clock (SSC: Source Sampling Clock), a source output enable (SOE: Source Output Enable) and a polarity control signal (POL: Polarity), etc. may include

In addition, the timing controller 140 converts the input RGB image signal into digital RGB image data in units of frames using the timing signal TS, and outputs the RBG image data to the data driver 130 and the dimming controller 160 . do. In this case, the timing signal TS includes a vertical synchronization signal V-sync, a horizontal synchronization signal H-sync, and a clock signal CLK.

The gate driver 120 generates a gate driving signal based on the gate control signal GCS and sequentially supplies the gate driving signal to the plurality of gate lines GL disposed on the liquid crystal panel 110 . The TFT formed in each sub-pixel is turned on by the gate driving signal.

The data driver 130 converts digital RGB image data supplied from the timing controller 140 into an analog image signal, that is, an analog RGB data voltage. In this case, digital RGB image data is converted into analog RGB data voltage by using the gamma voltage provided from the power supply unit.

Also, the data driver 130 supplies a data voltage to the plurality of data lines according to a timing when the TFTs of each sub-pixel are turned on based on the received data control signal DCS. A data voltage is supplied to the plurality of sub-pixels and a common voltage Vcom is supplied to the common electrode to display an image. At this time, the common voltage Vcom is generated by the power supply unit 190 and supplied to the common electrode. As another example, a common voltage Vcom may be generated by the data driver 130 and supplied to the common electrode.

Also, the timing controller 140 analyzes the input image signal to generate local dimming data LDD for individually driving the plurality of LED arrays 152 . At this time, a luminance value corresponding to each of the plurality of LED arrays 152 is calculated according to the brightness of the image. In addition, a dimming signal LDD for individually driving the plurality of LED arrays 152 is generated according to the respective luminance values of the plurality of LED arrays. Then, the generated dimming signal LDD is transmitted to the dimming control unit 170 .

4 is a diagram illustrating a dimming control unit 170 according to an embodiment of the present invention.

Referring to FIG. 4 , the dimming control unit 170 includes a dimming data generation unit 172 , a memory 174 , and an output unit 176 . First, in order to display a high-luminance image, a plurality of LED arrays emitting light with peak luminance are configured as a first LED array block. In addition, a plurality of LED arrays emitting light with a minimum luminance to display a low luminance image are configured as a second LED array block. In addition, a plurality of LED arrays disposed between the first LED array block and the second LED array block are configured as a third LED array block.

The memory 174 stores the size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block for each image pattern. As shown in FIG. 3 , the size value of the white pattern block 154 (the first LED array block) may be adjusted for each image pattern. 3 shows that the size values of the white pattern block 154 (the first LED array block) are set to 1.7%, 10%, and 25% of the total area, but this shows only some of the various embodiments of the present invention.

Here, the pattern of the image includes the horizontal and vertical aspect ratios of 21:9, 16:9, and 4:3. However, the present invention is not limited thereto, and the horizontal and vertical screen ratios may vary. In addition, the horizontal and vertical aspect ratios of the image pattern include 2.35:1 and 2.4:1.

The dimming data generator 172 analyzes the input dimming signal and sets the size of the first LED array block that emits light with a peak luminance according to an image pattern. In addition, the dimming data generator 172 sets a minimum duty value of the second LED array block that emits light with a low luminance.

The dimming data transmitted from the dimming data generating unit 172 to the output unit 174 includes the size value of the first LED array block emitting light at peak luminance and the minimum duty value of the second LED array block emitting light at low luminance. This is included.

In addition, the dimming data generation unit 172 analyzes the input dimming signal and when a pattern of an image not stored in the memory 174 is detected, the size value of the first LED array block of the detected new image pattern, the second A minimum duty value of the LED array block and a minimum duty value of the third LED array block are generated. And, the dimming data generating unit 172 is the new dimming data including the size value of the first LED array block of the detected new image pattern, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block. is updated in the memory 174.

The output unit 176 loads the size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block stored in the memory 174 according to the pattern of the image. to generate dimming data of the image pattern. Then, the dimming data of the image pattern is output to the LED driver 160 .

Here, the dimming data generator 172 adjusts a minimum duty value of a third LED array block disposed between the first LED array block and the second LED array block. The minimum duty value of the third LED array block is set to be smaller than the first duty value of the first LED array block. Then, the minimum duty value of the third LED array block is set to be greater than the second duty value of the second LED array block.

Specifically, when the first duty value of the first LED array block is 100% and the second duty value of the second LED array block is 0%, the minimum duty value of the third LED array block is 25% or less than 25% make it possible

When the peak luminance region and the low luminance region are disposed adjacent to each other, light from the peak luminance region enters the low luminance region and light leakage may occur. In the present invention, the minimum duty value of the third LED array block disposed between the first LED array block corresponding to the peak luminance region and the second LED array block corresponding to the low luminance region is adjusted to be 25% or less. Accordingly, it is possible to reduce the occurrence of light leakage into the low luminance region by reducing the luminance of a portion adjacent to the low luminance region.

The LED driver 160 includes a PWM converter and a voltage converter (boost power unit & buck power unit), and drives the plurality of LED arrays 152 according to the input dimming data.

Here, the PWM converter of the LED driver 160 adjusts the minimum duty values of the first LED array block, the second LED array block, and the third LED array block. The current supplied to the LED array 152 driven at the peak luminance may be increased through the boost power unit of the voltage converter. For example, assuming that the current value supplied in the general local dimming method is 100%, HDR driving may be applied to increase the current value supplied to the LED array emitting light with peak luminance to 150%. In addition, it is possible to lower the current supplied to the LED array 152 driven at low brightness through the buck power unit. For example, a current value supplied to an LED array emitting light with a low luminance may be reduced to 20%. Here, in order to prevent an increase in power consumption, the first power consumption when the global dimming is applied and the second power consumption when the local dimming is applied are made equal.

5 is a diagram illustrating a method of driving a liquid crystal display according to an embodiment of the present invention applied to a 21:9 aspect ratio.

Referring to FIG. 5 , in the 21:9 aspect ratio, area (1) is an area in which a logo of a broadcaster is displayed, and is an area in which a duty value and a peak luminance value are set. And, region (2) is a region where a caption is generated in the image region, and a peak luminance value is set. And, region (3) is a boundary region disposed between the peak luminance region and the low luminance region, and is a region in which luminance and minimum duty values are adjusted. And, region (4) is a region where a low luminance image is displayed, and is an region to which peak luminance is not applied. (4) The area corresponds to a portion in which subtitles are displayed in the movie content. And, region (5) is the lower end of the low luminance region and is a region to which the peak luminance is not applied. In the area (5), notification information of broadcast content is displayed in the form of a line.

A liquid crystal display device according to an embodiment of the present invention has a plurality of LEDs corresponding to regions (1), (2), (3), (4) and (5) for an image pattern having an aspect ratio of 21:9. The luminance value and duty value of each array can be individually set and applied. Through this, light leakage from the peak luminance region entering the low luminance region may be prevented.

6 is a diagram illustrating a method of driving a liquid crystal display according to an embodiment of the present invention applied to a 4:3 aspect ratio.

In the 4:3 aspect ratio, area (1) is the area where the logo of the broadcaster is displayed, and the area where the duty value and the peak luminance value are set. And, region (2) is a region where a caption is generated in the image region, and a peak luminance value is set. And, region (3) is a boundary region disposed between the peak luminance region and the low luminance region, and is a region in which luminance and minimum duty values are adjusted. And, region (4) is a region where a low luminance image is displayed, and is an region to which peak luminance is not applied. (4) The area corresponds to a portion in which subtitles are displayed in the movie content. And, region (5) is the lower end of the low luminance region and is a region to which the peak luminance is not applied. In the area (5), notification information of broadcast content is displayed in the form of a line.

A liquid crystal display device according to an embodiment of the present invention has a plurality of LEDs corresponding to regions (1), (2), (3), (4) and (5) for an image pattern having an aspect ratio of 4:3. The luminance value and duty value of each array can be individually set and applied. Through this, light leakage from the peak luminance region entering the low luminance region may be prevented.

7 is a diagram illustrating adjustment of a minimum duty value according to gray of an image when the horizontal and vertical aspect ratios of the image pattern have aspect ratios of 2.35:1 and 2.4:1.

Referring to FIG. 7 , a minimum duty value is set for each image pattern. In this case, when the horizontal and vertical aspect ratio of the image pattern is 2.35:1, the minimum duty value is set according to the gray of the image. The low luminance area having an aspect ratio of 2.35:1 is an area in which subtitles are displayed on the screen, and corresponds to areas (4) and (5) in FIGS. 5 and 6 above.

In addition, when the ratio of the horizontal and vertical screens of the low luminance area is 2.4:1, the minimum duty value is set according to the gray of the image. The low luminance area having an aspect ratio of 2.4:1 is an area in which subtitles are displayed on the screen, and corresponds to areas (4) and (5) in FIGS. 5 and 6 above.

When the horizontal and vertical aspect ratio of the image pattern is 2.4:1, light leakage can be prevented when the minimum duty value is set to 0.7% regardless of gray. and,

When the horizontal and vertical aspect ratio of the image pattern is 2.35:1, light leakage can be prevented when the minimum duty value in 31 gray is set to 0.7%. In addition, light leakage can be prevented when the minimum duty value is set to 0.9% in 63 gray. In addition, light leakage can be prevented when the minimum duty value is set to 1.8% at 127 gray. In addition, light leakage can be prevented when the minimum duty value is set to 13.0% in 191 gray. In addition, light leakage can be prevented when the minimum duty value is set to 42.7% in 223 gray. In addition, light leakage can be prevented when the minimum duty value is set to 42.7% in 255 gray.

8 is a diagram illustrating a luminance and current increase ratio for each size of a white pattern.

Referring to FIG. 8 , when the luminance (960 nit) is 100% in a screen pattern having an area of 100% of the peak luminance (full white), and the current (71mA) supplied to the LED array is set to 100%, the peak It shows the control of the luminance and the current value supplied to the LED array according to the aspect ratio.

When the area of peak luminance is 30%, it corresponds to region (5) shown in FIGS. 5 and 6, and the luminance of the LED array is increased to 138.1%, and the current value supplied to the LED array is increased to 147.9%. made it

And, when the area of the peak luminance is 25%, it corresponds to region (4) shown in FIGS. 5 and 6, and the luminance of the LED array is increased to 156.3%, and the value of the current supplied to the LED array is 167.6%. raised to And, when the area of the peak luminance is 20%, it corresponds to region (2) shown in FIGS. 5 and 6, and the luminance of the LED array is increased to 174.8%, and the current value supplied to the LED array is increased by 190.1%. raised to And, when the area of the peak luminance is 10%, it corresponds to region (3) shown in FIGS. 5 and 6, and the luminance of the LED array is increased to 238.4%, and the value of the current supplied to the LED array is increased by 242.3%. raised to And, when the area of the peak luminance is 5%, it corresponds to region (1) shown in FIGS. 5 and 6, and the luminance of the LED array is increased to 245.3%, and the value of the current supplied to the LED array is increased by 250.1%. raised to

As described above, by controlling the peak luminance value and the current value of the LED array according to the image pattern, light leakage from the peak luminance region into the low luminance region can be prevented or reduced.

The liquid crystal display device 100 of the present invention described above includes a liquid crystal panel 110 in which a plurality of subpixels are disposed, a plurality of light emitting diode (LED) arrays 152 disposed under the liquid crystal panel 110 , and It includes a driving circuit unit. The driving circuit unit includes a timing controller 140 , a dimming control unit 170 , and an LED driver 160 . The timing controller 140 analyzes the input image signal to generate dimming signals of the plurality of LED arrays 152 . Then, the dimming control unit 170 analyzes the dimming signal and sets the size of the first LED array block that emits light with a peak luminance according to an image pattern. In addition, the dimming control unit 170 sets a minimum duty value of the second LED array block that emits light with a low luminance. And, the dimming data including the size value of the first LED array block and the minimum duty value of the second LED array block is generated. In addition, the LED driver 160 drives the plurality of LED arrays 152 according to the dimming data.

In addition, the liquid crystal display device 100 of the present invention adjusts the minimum duty value of the third LED array block disposed between the first LED array block and the second LED array block.

In addition, the liquid crystal display device 100 of the present invention further includes a memory in which the size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block are stored. . And, the dimming data by loading the size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block stored in the memory according to the pattern of the image create

The liquid crystal display device 100 of the present invention sets the minimum duty value of the third LED array block to be smaller than the first duty value of the first LED array block. Then, the minimum duty value of the third LED array block is set to be greater than the second duty value of the second LED array block.

Here, the horizontal and vertical aspect ratios of the image pattern may be 21:9, 16:9, and 4:3. In addition, the horizontal and vertical aspect ratios of the image pattern may be 2.35:1 and 2.4:1.

The liquid crystal display device 100 of the present invention adjusts a luminance value of each of the plurality of LED arrays 152 and a current value supplied to each of the plurality of LED arrays 252 for each position on the entire screen.

In the above-described driving method of the liquid crystal display device of the present invention, a dimming signal of a plurality of LED arrays is generated by analyzing an input image signal. Thereafter, the dimming signal is analyzed to set a size value of the first LED array block that emits light with a peak luminance according to an image pattern. Then, a minimum duty value of the second LED array block that emits light with a low luminance is set. Thereafter, dimming data including a size value of the first LED array block and a minimum duty value of the second LED array block is generated. Then, the plurality of LED arrays are driven according to the dimming data.

In the method of driving a liquid crystal display device of the present invention, a minimum duty value of a third LED array block disposed between the first LED array block and the second LED array block is adjusted. The size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block are stored in a memory.

In the method of driving a liquid crystal display device of the present invention, the minimum duty value of the third LED array block is set to be smaller than the first duty value of the first LED array block. Then, the minimum duty value of the third LED array block is set to be greater than the second duty value of the second LED array block. Here, the minimum duty value of the third LED array block is included in the dimming data.

In the method of driving a liquid crystal display device of the present invention, a luminance value of each of the plurality of LED arrays and a current value supplied to each of the plurality of LED arrays are adjusted for each position on the entire screen.

The liquid crystal display device and the driving method thereof of the present invention can reduce light leakage during high dynamic range (HDR) driving by setting the size of an LED array block that emits light with peak luminance according to an image pattern (eg, aspect ratio). .

In addition, it is possible to reduce light leakage during high dynamic range (HDR) driving by adjusting the minimum duty value of the LED array block that emits light with low luminance according to an image pattern (eg, aspect ratio).

In addition, it is possible to reduce light leakage during high dynamic range (HDR) driving by adjusting the minimum duty value of the LED array block disposed between the LED array block emitting light with a peak luminance and the LED array block emitting light with a low luminance.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention may be embodied in other specific forms without changing the technical spirit or essential characteristics thereof.

Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

100: liquid crystal display device
110: liquid crystal panel
120: gate driver
130: data driver
140: timing controller
150: backlight unit
160: LED driver
170: dimming control unit
172: dimming data generation unit
174: memory
176: output unit

Claims (11)

a liquid crystal panel on which a plurality of sub-pixels are disposed;
a plurality of light emitting diode (LED) arrays disposed under the liquid crystal panel;
a timing controller that analyzes the input image signal to generate dimming signals of the plurality of LED arrays;
By analyzing the dimming signal, the size of the first LED array block that emits light with peak luminance is set according to the pattern of the image, and the dimming data in which the minimum duty value of the second LED array block that emits light with low luminance is set is generated. a dimming control unit; and
an LED driver for driving the plurality of LED arrays according to the dimming data;
The dimming control unit adjusts a size of the first LED array block and a minimum duty value of the second LED array block according to an aspect ratio of the image pattern. According to claim 1,
A liquid crystal display device for adjusting a minimum duty value of a third LED array block disposed between the first LED array block and the second LED array block. 3. The method of claim 2,
Further comprising a memory in which the size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block are stored,
Generating the dimming data by loading the size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block stored in the memory according to the pattern of the image liquid crystal display device. 3. The method of claim 2,
The minimum duty value of the third LED array block is set to be smaller than the first duty value of the first LED array block, and the minimum duty value of the third LED array block is greater than the second duty value of the second LED array block. Liquid crystal display device to set. According to claim 1,
A liquid crystal display having a horizontal and vertical aspect ratio of the image pattern of 21:9, 16:9, and 4:3. According to claim 1,
A liquid crystal display device having a horizontal and vertical aspect ratio of the image pattern of 2.35:1 and 2.4:1. According to claim 1,
A liquid crystal display device for controlling a luminance value of each of the plurality of LED arrays and a current value supplied to each of the plurality of LED arrays for each position on the entire screen. generating dimming signals of a plurality of LED arrays by analyzing the input image signals;
analyzing the dimming signal to set a size of a first LED array block emitting light with a peak luminance according to a pattern of an image, and setting a minimum duty value of a second LED array block emitting light with a low luminance;
generating dimming data including a size value of the first LED array block and a minimum duty value of the second LED array block; and
Including; driving the plurality of LED arrays according to the dimming data;
Setting the size of the first LED array block and setting the minimum duty value of the second LED array block comprises:
A method of driving a liquid crystal display device for adjusting a size of the first LED array block and adjusting a minimum duty value of the second LED array block according to an aspect ratio of the image pattern. 9. The method of claim 8,
adjusting a minimum duty value of a third LED array block disposed between the first LED array block and the second LED array block; and
and storing the size value of the first LED array block, the minimum duty value of the second LED array block, and the minimum duty value of the third LED array block in a memory. 10. The method of claim 9,
The minimum duty value of the third LED array block is set to be smaller than the first duty value of the first LED array block, and the minimum duty value of the third LED array block is greater than the second duty value of the second LED array block. set up,
A method of driving a liquid crystal display device including a minimum duty value of the third LED array block in dimming data. 11. The method of claim 10,
A method of driving a liquid crystal display device for controlling a luminance value of each of the plurality of LED arrays and a current value supplied to each of the plurality of LED arrays for each position on the entire screen.

Images