KR102404464B1 - 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 main controller, a timing controller, and an LED driver. The main controller generates first dimming data for global dimming by analyzing the input image signal. Then, BPL command data for driving Boost Peak Luminance (BPL) is generated. The timing controller generates second dimming data for local dimming by analyzing the image signal. Then, the BPL command data and the second dimming data are included in packet data and output. When the BPL driving is applied, based on the first dimming data and the second dimming data, when the local dimming versus global dimming is applied, the LED driver is configured to reduce power consumption within a range of reducing power consumption. Increase the current supplied to the array.

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 driving Boost Peak Luminance (BPL) and Smart Black, 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.

2 is a diagram illustrating a method of driving an LED array in a normal mode (local dimming) and a boost peak luminance (BPL) mode.

Referring to FIG. 2 , when a plurality of LED arrays are driven in the normal mode by applying general local dimming, the luminance of each LED array is adjusted by adjusting the duty based on the maximum current value. In addition, when the BPL mode is applied, the maximum current value of each LED array is increased, and the luminance of each LED array is adjusted by decreasing the duty by the increased current value.

Here, the area A1 during the dimming-on period when the first LED array is driven in the normal mode is the same as the area A2 during the dimming-on period when the first LED array is driven in the BPL mode. Also, the area B1 during the dimming-on period when the second LED array is driven in the normal mode is the same as the area B2 during the dimming-on period when the second LED array is driven in the BPL mode. Also, the area C1 during the dimming-on period when the third LED array is driven in the normal mode is the same as the area C2 during the dimming-on period when the third LED array is driven in the BPL mode.

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. In order to implement HDR in the prior art, since the luminance of the LED array must be increased, there is a problem in that power consumption increases due to the increase in the luminance of the LED array. In addition, on an overall bright screen, the LED array is lit with excessively high luminance, and thus there is a problem in that display quality is deteriorated.

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

The present invention is to solve the above-described problems, and it is a technical task to provide a liquid crystal display device capable of improving display quality by applying Boost Peak Luminance (BPL) and Smart Black driving and a driving method thereof. do.

An object of the present invention is to provide a liquid crystal display device that does not increase power consumption by locally increasing the luminance of an LED array during BPL driving, and a method for driving the same.

The present invention is to solve the above-described problems, and it is a technical task to provide a liquid crystal display device capable of improving the contrast ratio of an image by locally increasing the luminance of an LED array during BPL driving and a driving method thereof. do.

An object of the present invention is to provide a liquid crystal display device capable of reducing detection of a difference in luminance between a bright screen and a dark screen during BPL driving, and a driving method thereof.

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 main controller, a timing controller, and an LED driver. The main controller generates first dimming data for global dimming by analyzing the input image signal. Then, BPL command data for driving Boost Peak Luminance (BPL) is generated. The timing controller generates second dimming data for local dimming by analyzing the image signal. Then, the BPL command data and the second dimming data are included in packet data and output. When the BPL driving is applied, the LED driver is based on the first dimming data and the second dimming data, and when applying local dimming versus global dimming, one or more LEDs of the plurality of LED arrays within a reduced power consumption range Increase the current supplied to the array.

In order to achieve the above-described technical problem, a method of driving a liquid crystal display device of the present invention generates first dimming data for global dimming by analyzing an input image signal. In addition, BPL command data for BPL (Boost Peak Luminance) driving is generated. Thereafter, second dimming data for local dimming is generated by analyzing the image signal. Then, the BPL command data and the second dimming data are included in packet data and output. Then, when applying the BPL driving, based on the first dimming data and the second dimming data, when applying local dimming versus global dimming, the power consumption is reduced in one or more LED arrays of the plurality of LED arrays. Increase the supplied current.

The liquid crystal display device and the driving method thereof of the present invention can improve display quality by applying boost peak luminance (BPL) and smart black driving.

The liquid crystal display device of the present invention and its driving method do not increase power consumption even when the luminance of the LED array is locally increased during BPL driving.

The liquid crystal display device and the driving method thereof of the present invention can improve the contrast ratio of an image by locally increasing the luminance of the LED array during BPL driving.

The liquid crystal display device and the driving method thereof of the present invention limit the PWM duty of the LED array to which the minimum value of local dimming is applied to be greater than or equal to a predetermined value, thereby reducing the detection of a luminance difference between a bright screen and a dark screen.

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 method of driving an LED array in a normal mode (local dimming) and a boost peak luminance (BPL) mode.
3 is a diagram illustrating a liquid crystal display device according to an embodiment of the present invention.
4 is a diagram illustrating an LED driver according to an embodiment of the present invention.
5 and 6 are diagrams illustrating a method of driving a liquid crystal display device according to an exemplary embodiment of the present invention.

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 make the disclosure of the present invention 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.

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

Referring to FIG. 3 , 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 main 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.

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.

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 emit light to the liquid crystal panel 110 . ) direction, and may include an optical member (not shown) for improving light efficiency. In FIG. 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 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 addition, the plurality of LED arrays 152 may be driven by the BPL method.

The main controller 170 analyzes the input Youngsan signal to calculate a PWM duty value of the entire LED array 152 . Then, the PWM duty value of the entire LED array 152 is generated as first dimming data (GDD, global dimming data) and supplied to the LED driver 160 . Also, the main controller 170 generates BPL command data for BPL driving and supplies the BPL command data to the timing controller. In this case, the BPL command data indicates on/off of the BPL driving, and may be transmitted from the main controller 170 to the timing controller 140 using an I2C (inter integrated circuit) communication method. Also, the main controller 170 transmits the input image signal and the timing signal TS to the time controller 140 .

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 second dimming data (LDD, local dimming data) 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, second dimming data (LDD, local dimming data) for individually driving the plurality of LED arrays 152 according to the respective luminance values of the plurality of LED arrays is generated.

As shown in Table 1 below, the timing controller 140 transmits the BPL command data and the second dimming data to the LED driver 160 by including the BPL command data and the second dimming data in the packet data.

As shown in Table 1, BPL command data indicating on/off of BPL driving is included in bit 5 of the command byte. When the BPL driving is off, the maximum current value is limited to 100%, and the PWM duty can be set to 100% to 0%. Meanwhile, when BPL driving is turned on, the maximum current value may be increased to 160%, and the PWM duty may be set to 100% to 20%. Here, the packet data may be transmitted from the timing controller 140 to the LED driver 160 using a Serial Peripheral Interface (SPI) communication method.

4 is a diagram illustrating an LED driver according to an embodiment of the present invention.

Referring to FIG. 4 , the LED driver 160 includes a first driving unit 164 , a second driving unit 162 , and an LED drive IC 166 . Here, the LED drive IC 166 includes a PWM converter and a voltage converter (boost power unit & buck power unit). When the PLD driving is turned on by the BPL command data, the first driving unit 164 calculates the average value, the minimum value, and the maximum value of the local dimming of the plurality of LED arrays based on the input second dimming data. Calculate. Then, the first driving unit 164 calculates the PWM duty value and the current value of each LED array 152 . The calculated average value, minimum value, and maximum value of the local dimming of the LED array, and the PWM duty value and current value of the LED array 152 are transmitted to the second driver 162 .

Here, the first driving unit 164 calculates the first power consumption when the global dimming is applied and the second power consumption when the local dimming is applied. BPL driving may be achieved by increasing the current supplied to one or more of the LED arrays 152 of the LED array. In this case, assuming that the current value during local dimming is 100%, the current value may be increased to 160% during BPL driving.

Also, the first driver 164 may adjust the PWM duty of one or more LED arrays to which the minimum value of local dimming is applied according to a difference between the maximum value of local dimming and the minimum value of local dimming. At this time, the PWM duty value can be adjusted within the range of 100% to 20%.

The second driver 162 drives the LED drive IC 166 according to the first dimming data (global dimming data) when the BPL driving is turned off. In addition, when the BPL driving is turned on, the second driver 162 drives the LED drive IC 166 based on the PWM duty value and the current value input from the first driver 164 .

A multi-channel drive IC is applied to the LED drive IC 166 and drives the plurality of LED arrays 152 based on the first dimming data or the second dimming data.

The PWM converter of the LED drive IC 166 generates a PWM signal according to the input dimming data, and supplies the generated PWM signal to the voltage converter. A buck power conversion unit and a boost power unit are applied to the voltage conversion unit of the LED drive IC 166. A plurality of LEDs using a buck power unit A current value of each of the arrays 152 may be decreased, and a current value of each of the plurality of LED arrays 152 may be increased by using a boost power unit.

5 and 6 are diagrams illustrating a method of driving a liquid crystal display device according to an exemplary embodiment of the present invention.

5 and 6 , a current value supplied to the LED array in a portion corresponding to a bright screen may be increased by using a boost power unit. For example, assuming that the current value supplied in the general local dimming method is 100%, the current value supplied to the LED array to which the BPL driving is applied may be increased to 160%. In addition, the PWM duty value of the LED array to which BPL driving is applied can be reduced to a level of 67%.

Therefore, the first area value obtained by multiplying the current value of the LED array by the PWM duty value (current * PWM duty) when applying the general local dimming driving, and the current value of the LED array multiplied by the PWM duty value when applying the BPL driving ( Current * PWM duty) The second area value becomes the same. That is, it is possible to prevent an increase in power consumption by reducing the PWM duty by the increased current value.

Here, the difference in luminance with the dark portion may be recognized by the high luminance of the LED array to which the BPL driving is applied. In the present invention, the perceived difference in luminance is reduced by applying smart black driving.

For example, when the difference between the maximum value (Max) of local dimming and the minimum value (Min) of local dimming is severe, the PWM duty is not lowered below a certain value in the LED array to which the minimum dimming value is applied. limit the value.

As a specific example, the LED driver 160 calculates an average value, a minimum value, and a maximum value of local dimming of the plurality of LED arrays. And, according to a difference between the maximum value of the local dimming and the minimum value of the local dimming, the PWM duty of one or more LED arrays to which the minimum value of the local dimming is applied is adjusted.

When the liquid crystal display device 100 displays an image in the TV mode, if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 100%, at least one LED array to which the minimum value of the local dimming is applied. PWM duty can be limited to 30%.

And, when the liquid crystal display device 100 displays an image in TV mode, if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 65%, one or more LEDs to which the minimum value of the local dimming is applied You can limit the PWM duty of the array to 25%.

And, when the liquid crystal display device 100 displays an image in the TV mode, if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 20%, one or more LEDs to which the minimum value of the local dimming is applied You can limit the PWM duty of the array to 20%.

When the liquid crystal display device 100 displays an image in the TV mode, when the difference between the maximum value of the local dimming and the minimum value of the local dimming is 99% to 66%, the minimum value of one or more LED arrays is applied. The PWM duty can be limited within the range of 30% to 25%. In addition, when the difference between the maximum value of the local dimming and the minimum value of the local dimming is 64% to 21%, the PWM duty of one or more LED arrays to which the minimum value is applied can be limited within the range of 25% to 20%. have.

As another example of the present invention, when the liquid crystal display device 100 displays an image in the PC mode, if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 100%, the minimum value of the local dimming is It is possible to limit the PWM duty of one or more LED arrays applied to 50%.

And, when the liquid crystal display device 100 displays an image in TV mode, if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 65%, one or more LEDs to which the minimum value of the local dimming is applied You can limit the PWM duty of the array to 35%.

And, when the liquid crystal display device 100 displays an image in the TV mode, if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 20%, one or more LEDs to which the minimum value of the local dimming is applied You can limit the PWM duty of the array to 20%.

When the liquid crystal display device 100 displays an image in the TV mode, when the difference between the maximum value of the local dimming and the minimum value of the local dimming is 99% to 66%, the minimum value of one or more LED arrays is applied. The PWM duty can be limited within the range of 50% to 35%. In addition, when the difference between the maximum value of the local dimming and the minimum value of the local dimming is 64% to 21%, the PWM duty of one or more LED arrays to which the minimum value is applied can be limited within the range of 35% to 20%. have.

The liquid crystal display device 100 of the present invention can improve display quality by applying boost peak luminance (BPL) and smart black driving. In addition, even if the brightness of the LED array is locally increased during BPL driving, power consumption is not increased.

The liquid crystal display device 100 of the present invention can improve the contrast ratio of an image by locally increasing the luminance of the LED array during BPL driving. In addition, by limiting the PWM duty of the LED array to which the minimum value of local dimming is applied during BPL driving to a certain value or more, it is possible to reduce the detection of a luminance difference between a bright screen and a dark screen.

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
164: first driving unit
162: second driving unit
166: LED drive IC
170: main controller

Claims (13)

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 main controller that analyzes the input image signal to generate first dimming data for global dimming, and generates BPL command data for driving boost peak luminance (BPL);
a timing controller for generating second dimming data for local dimming by analyzing the video signal, and outputting the BPL command data and the second dimming data by including the second dimming data in packet data; and
When the BPL driving is applied, based on the first dimming data and the second dimming data, when local dimming is applied compared to global dimming, the power consumption is reduced within a range that is supplied to one or more LED arrays among the plurality of LED arrays A liquid crystal display device comprising a; LED driver for increasing the current. According to claim 1,
The BPL so that the first area value obtained by multiplying the current value of the LED array by the PWM duty value when the local dimming driving is applied and the second area value obtained by multiplying the current value of the LED array by the PWM duty value when the BPL driving is applied are the same. A liquid crystal display device that adjusts the current value and PWM duty value of the LED array when driving is applied. According to claim 1,
A liquid crystal display device in which the maximum current value of the LED array to which local dimming is applied is set to 100%, and the maximum current value of the LED array to which BPL driving is applied is set to 160%. According to claim 1,
A liquid crystal display device that sets the PWM duty value of the LED array to which local dimming is applied to 100% and adjusts the PWM duty value of the LED array to which BPL driving is applied in the range of 100% to 20%. 5. The method of claim 4,
The LED driver is
calculating an average value, a minimum value, and a maximum value of local dimming of the plurality of LED arrays,
A liquid crystal display device for adjusting PWM duty of one or more LED arrays to which the minimum value of the local dimming is applied according to a difference between the maximum value of the local dimming and the minimum value of the local dimming. 6. The method of claim 5,
If the difference between the maximum value of the local dimming and the minimum value of the local dimming is 100%,
A liquid crystal display device for limiting the PWM duty of one or more LED arrays to which the minimum value of local dimming is applied to 30%. 6. The method of claim 5,
If the difference between the maximum value of the local dimming and the minimum value of the local dimming is 65%,
A liquid crystal display device for limiting the PWM duty of one or more LED arrays to which the minimum value of local dimming is applied to 25%. 6. The method of claim 5,
If the difference between the maximum value of the local dimming and the minimum value of the local dimming is 20%,
A liquid crystal display device for limiting the PWM duty of one or more LED arrays to which the minimum value of local dimming is applied to 20%. generating first dimming data for global dimming by analyzing the input image signal, and generating BPL command data for driving boost peak luminance (BPL);
generating second dimming data for local dimming of a plurality of LED arrays by analyzing the image signal, and outputting the BPL command data and the second dimming data included in packet data; and
When the BPL driving is applied, based on the first dimming data and the second dimming data, when local dimming is applied compared to global dimming, the power consumption is reduced within a range that is supplied to one or more LED arrays among the plurality of LED arrays A method of driving a liquid crystal display device comprising the step of increasing the current. 10. The method of claim 9,
The BPL so that the first area value obtained by multiplying the current value of the LED array by the PWM duty value when the local dimming driving is applied and the second area value obtained by multiplying the current value of the LED array by the PWM duty value when the BPL driving is applied are the same. When applying driving, adjust the current value and PWM duty value of the LED array,
A driving method of a liquid crystal display device in which PWM duty is reduced as much as the maximum current value of an LED array to which BPL driving is applied increases. 11. The method of claim 10,
Set the PWM duty value of the LED array to which local dimming is applied to 100%, and adjust the PWM duty value of the LED array to which BPL driving is applied in the range of 100% to 20%,
When the difference between the maximum value of the local dimming and the minimum value of the local dimming is 100%, the driving method of the liquid crystal display device for limiting the PWM duty of one or more LED arrays to which the minimum value of the local dimming is applied to 30%. 12. The method of claim 11,
When the difference between the maximum value of the local dimming and the minimum value of the local dimming is 65%, the method of driving a liquid crystal display device for limiting the PWM duty of one or more LED arrays to which the minimum value of the local dimming is applied to 25%. 12. The method of claim 11,
When the difference between the maximum value of the local dimming and the minimum value of the local dimming is 20%, the method of driving a liquid crystal display device for limiting the PWM duty of one or more LED arrays to which the minimum value of the local dimming is applied to 20%.

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