KR20170026024A - Liquid Display Device And Method Of Driving The Same - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method for driving the same, which can improve display quality by boost peak luminance (BPL) and smart black driving. The liquid crystal display device of the present invention comprises: a liquid crystal panel having a plurality of subpixels disposed thereon; a plurality of light emitting diode (LED) arrays disposed under the liquid crystal panel; and a driving circuit unit. 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 an input image signal and generates BPL command data for the BPL driving. The timing controller generates second dimming data for local dimming by analyzing the image signal and outputs the BPL command data and the second dimming data while including the BPL command data and the second dimming data in packet data. The LED driver increases current supplied to at least one of the LED arrays within the range in which power consumption is reduced when applying the local dimming compared to the global dimming, based on the first dimming data and the second dimming data, when applying the BPL driving.

Description

[0001] The present invention relates to a liquid crystal display device and a method of driving the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of improving display quality by BPL (Boost Peak Luminance) and Smart Black driving and a driving method thereof.

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

Since the liquid crystal display device is not a self-luminous device, images are 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 maximized, the liquid crystal panel realizes a white image with high brightness. On the contrary, when the transmittance of light of the liquid crystal layer is minimized, the liquid crystal panel realizes a black image with low brightness.

Conventional liquid crystal display devices display images by irradiating light with a maximum luminance in a backlight unit and adjusting the amount of light transmitted through a backlight unit according to an electric field applied in units of a unit cell in a liquid crystal panel. Therefore, the light transmission amount of the liquid crystal cell changes according to the image data supplied to each of the sub pixels, and the luminance of the image displayed on the liquid crystal panel changes due to the light transmission amount.

1 is a view showing a plurality of LED arrays arranged in a backlight unit of a liquid crystal display device according to the related art. 1, a plurality of LEDs (light emitting diode) arrays are shown in the configuration of a backlight unit, and optical members (diffusion plates and optical sheets) are not shown.

1, a plurality of LED arrays 10 (for example, 80 LED arrays) are arranged in a backlight unit 1, and a plurality of LEDs 12 are arranged in each LED array 10 . As the importance of low power consumption and DCR (Dynamic Contrast Ratio) increases, global dimming and local dimming methods which operate the brightness of image data and backlight in conjunction with each other, Interest in the same dynamic driving method is increasing. The global dimming scheme drives the plurality of LED arrays 10 to the same dimming value. On the other hand, the local dimming scheme drives each of the plurality of LED arrays 10 to an individual dimming value.

2 is a diagram illustrating a method of driving an LED array in a normal mode (local dimming) and a BPL (Boost Peak Luminance) mode.

Referring to FIG. 2, when driving a plurality of LED arrays in the normal mode by applying general local dimming, the duty of each LED array is adjusted based on the maximum current value. When applying the BPL mode, the maximum current value of each LED array is increased, and the duty of the increased current value is decreased to adjust the brightness of each LED array.

Here, when driving the first LED array in the normal mode, the area A1 for the dimming on period and the dimming on period interval A2 for driving the first LED array in the BPL mode are the same. In addition, the area B1 for the dimming ON period when the second LED array is driven in the normal mode and the area B2 of the dimming ON duration when the second LED array is driven in the BPL mode are the same. In addition, the area C1 during the dimming on period when the third LED array is driven in the normal mode and the area C2 during dimming on interval when the third LED array is driven in the BPL mode are the same.

Recently, there is an increasing demand for a liquid crystal display device to which HDR (High Dynamic Range) technology capable of realizing a high image quality is applied. In order to implement HDR in the prior art, the brightness of the LED array must be increased, and the power consumption is increased due to the increase of the brightness of the LED array. In addition, in a bright screen as a whole, there is a problem that the LED array is illuminated with an excessively high luminance and the display quality is deteriorated.

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

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a liquid crystal display device and a driving method thereof that can improve display quality by applying BPL (Boost Peak Luminance) and Smart Black do.

SUMMARY OF THE INVENTION The present invention is directed to a liquid crystal display device and a method of driving the same that does not increase power consumption by raising the brightness of an LED array locally during BPL driving.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a liquid crystal display device and a method of driving the same that can enhance the contrast ratio of an image by raising the brightness of an LED array locally during BPL driving do.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a liquid crystal display device and a method of driving the same that can reduce the luminance difference detection of a bright screen and a dark screen.

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims.

According to an aspect of the present invention, there is provided a liquid crystal display device including a liquid crystal panel in which a plurality of sub-pixels are disposed, a plurality of light emitting diode arrays arranged in a lower portion of the liquid crystal panel, . The driving circuit section includes a main controller, a timing controller, and an LED driver. The main controller analyzes the input video signal to generate first dimming data for global dimming. Then, BPL command data for driving BPL (Boost Peak Luminance) is generated. The timing controller analyzes the video signal to generate second dimming data for local dimming. The BPL command data and the second dimming data are included in the packet data and output. Wherein the LED driver is configured to apply the first dimming data and the second dimming data when the BPL drive is applied to the at least one LED of the plurality of LED arrays Raising the current supplied to the array.

According to an aspect of the present invention, there is provided a method of driving a liquid crystal display device, the method including the steps of: generating first dimming data for global dimming by analyzing an input video signal; In addition, BPL command data for driving BPL (Boost Peak Luminance) is generated. Thereafter, the image signal is analyzed to generate second dimming data for local dimming. The BPL command data and the second dimming data are included in the packet data and output. Thereafter, based on the first dimming data and the second dimming data when the BPL drive is applied, in the range where power consumption is reduced when applying global dimming versus local dimming, the one or more LED arrays Thereby raising the supplied current.

The liquid crystal display device and the driving method of the present invention can improve the display quality by applying BPL (Boost Peak Luminance) and Smart Black driving.

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

The liquid crystal display device and the driving method thereof according to the present invention can enhance the contrast ratio of an image by raising the brightness of the LED array locally when driving the BPL.

The liquid crystal display device and the driving method of the present invention can limit the PWM duty of the LED array to which the minimum value of the local dimming is applied to be more than a predetermined value to reduce the luminance difference detection of the bright screen and the dark screen.

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

1 is a view showing a plurality of LED arrays arranged in a backlight unit of a liquid crystal display device according to the related art.
2 is a diagram illustrating a method of driving an LED array in a normal mode (local dimming) and a BPL (Boost Peak Luminance) mode.
3 is a view illustrating a liquid crystal display device according to an embodiment of the present invention.
4 is a view illustrating an LED driver according to an embodiment of the present invention.
5 and 6 are views showing a driving method of a liquid crystal display device according to an embodiment of the present invention.

Like reference numerals throughout the specification denote substantially identical components. In the following description, detailed descriptions of configurations and functions known in the technical field of the present invention and those not related to the core configuration of the present invention can be omitted. The meaning of the terms described herein should be understood as follows.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. To fully disclose the scope of the invention to a person skilled in the art, and the invention is only defined by the scope of the claims.

It should be noted that, in the specification of the present invention, the same reference numerals as in the drawings denote the same elements, but they are numbered as much as possible even if they are shown in different drawings.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if the temporal relationship is described by 'after', 'after', 'after', 'before', etc., May not be continuous unless they are not used.

The term " at least one " should be understood to include all possible combinations from 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, but also the second item, the second item and the third item, Means any combination of items that can be presented from more than one.

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

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

The liquid crystal display device has been developed in various ways such as TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode according to a method of adjusting the arrangement of liquid crystal layers.

In the TN mode and the VA mode, 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 alignment of the liquid crystal layer 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 alignment of the liquid crystal layer with a horizontal electric field between the pixel electrode and the common electrode.

In the IPS mode, the pixel electrode and the common electrode are alternately arranged in parallel to each other to generate a horizontal electric field between the two electrodes to adjust the alignment of the liquid crystal layer. In the FFS mode, the pixel electrode and the common electrode are spaced apart with an insulating layer therebetween. At this time, one electrode is formed in a plate shape or a pattern and the other electrode is formed in a finger shape, and the arrangement of the liquid crystal layer is controlled through a fringe field generated between the electrodes Method. The liquid crystal panel according to the embodiment of the present invention can be applied to both the vertical electric field system (TN mode, VA mode) and the horizontal electric field system (IPS mode, FFS mode) without limitation of mode.

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 view illustrating a liquid crystal display device according to an embodiment of the present invention.

Referring to FIG. 3, a 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.

The driving circuit includes a gate driver 120, a data driver 130, a timing controller 140, an LED driver 160, and a main controller 170. And a power supply unit (not shown) for supplying power to the liquid crystal panel 110 and the driving circuit unit. All or a part of the driving circuit portion may be disposed on the liquid crystal panel 110 in a COG (Chip On Glass) or COF (Chip On Flexible Printed Circuit) method.

The liquid crystal panel 110 is constructed by bonding a first substrate (TFT array substrate) and a second substrate (color filter array substrate) 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 non-display area in a pad area PA. The pad region PA is disposed outside the active region A / A.

On the second substrate (color filter array substrate), RGB color filters are arranged so as to correspond to the respective sub pixels. A black matrix for defining an aperture region of each sub pixel and preventing color mixing is arranged.

A plurality of subpixels are arranged in a matrix form on a first substrate (TFT array substrate), and a plurality of subpixels are defined by a plurality of data lines and a plurality of gate lines crossing each other . R, G, and B subpixels gather to form one pixel. In each sub-pixel, a switching TFT, 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 for each of a plurality of sub-pixels. The pixel electrode and the common electrode are formed of a transparent conductive material such as ITO (Indium Tin Oxide).

In addition, the liquid crystal display device according to the present invention may be used in various forms known in the art such as TN (Twisted Nematic) mode, IPS (In-Plane Switching) mode, VA (Vertical Alignment) mode, FSS Can be applied. The configurations of the first substrate and the second substrate may be variously changed according to the various modes.

The backlight unit 150 includes a plurality of LED arrays 152 on which LEDs for generating light to be irradiated to the liquid crystal panel 110 are disposed and a plurality of LED arrays 152 arranged on the plurality of LED arrays 152, (Not shown) for guiding light toward the light guide plate (not shown) and improving the light efficiency. In Fig. 3, the optical member is not shown. The optical member includes a diffusion plate for uniformly irradiating light radiated from the plurality of LED arrays 152 across the entire surface of the liquid crystal panel 110, a prism sheet for enhancing light efficiency by condensing the light emitted from the diffusion plate, And a polarizing sheet that polarizes light.

A plurality of LED arrays 152 are arranged in the backlight unit 150, and a plurality of LEDs are arranged in each of the LED arrays. In the plurality of LED arrays 152, two or more LEDs are arranged, and each LED is turned on via a driving power supply line and a driving power supplied from the ground line. At this time, each of the LED arrays 152 may be driven individually, or a certain number of the LED arrays 152 may be driven in units of blocks, under the control of the LED driver 160. Here, the plurality of LED arrays 152 may be driven by a global dimming method or by 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 signal to calculate the 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. Further, the main controller 170 generates BPL command data for BPL driving and supplies BPL command data to the timing controller. At this time, the BPL command data indicates on / off of the BPL drive and can be transmitted from the main controller 170 to the timing controller 140 in an inter integrated circutit (I2C) communication method. Also, the main controller 170 transmits the input video signal and the timing signal TS to the controller 140.

The timing controller 140 generates a gate control signal (GCS: Gate Control Signal) for controlling the gate driver 120 by 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).

The timing controller also generates a data control signal (DCS: Data Control Signal) for controlling the data driver 130 using the timing signal TS and supplies it to the data driver 130. The data control signal DCS includes a source start pulse (SSP), a source sampling clock (SSC), a source output enable (SOE) and a polarity control signal (POL) . ≪ / RTI >

The timing controller 140 converts the input RGB video signal into digital RGB video data using the timing signal TS and outputs the RBG video data to the data driver 130 and the dimming control unit 160 do. At this time, 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 a gate driving signal to a plurality of gate lines GL arranged in 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 the digital RGB image data supplied from the timing controller 140 into an analog image signal, that is, an analog RGB data voltage. At this time, the digital RGB image data is converted into the analog RGB data voltage by using the gamma voltage supplied from the power supply unit.

In addition, the data driver 130 supplies the data voltages to the plurality of data lines in accordance with the timing at which the TFTs of the subpixels are turned on, based on the received data control signal DCS. A data voltage is supplied to a plurality of subpixels, and a common voltage Vcom is supplied to the common electrode to display an image. At this time, a common voltage Vcom is generated in the power supply unit 190 and supplied to the common electrode. As another example, the common voltage Vcom may be generated in the data driver 130 and supplied to the common electrode.

The timing controller 140 analyzes the input video signal and generates second dimming data (LDD) for driving the plurality of LED arrays 152 individually. At this time, the luminance value corresponding to each of the plurality of LED arrays 152 is calculated according to the brightness of the image. Then, second dimming data (LDD, local dimming data) for individually driving the plurality of LED arrays 152 is generated according to the luminance value of each of the plurality of LED arrays.

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 in the packet data.

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

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

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

Here, the first driver 164 calculates the first power consumption when the global dimming is applied and the second power consumption when the local dimming is applied, and when the local dimming is applied, The current supplied to one or more LED arrays of the LED arrays 152 may be increased to drive the BPL. At this time, assuming that the current value at the time of local dimming is 100%, the current value at the time of BPL driving can be increased to 160%.

In addition, the first driver 164 may adjust the PWM duty of the one or more LED arrays to which the minimum value of local dimming is applied, depending on the 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%.

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

The LED drive IC 166 applies a multi-channel drive IC 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 in accordance with the input dimming data, and supplies the generated PWM signal to the voltage converter. A buck power unit and a boost power unit are applied to the voltage conversion unit of the LED drive IC 166. A buck power unit is used to convert a plurality of LEDs The current value of each of the plurality of LED arrays 152 can be increased by using a boost power unit.

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

Referring to FIGS. 5 and 6, a current value supplied to the LED array corresponding to the bright screen can be increased by using a boost power unit. For example, assuming that the current value supplied from the general local dimming method is 100%, the current value supplied to the LED array to which the BPL drive is applied can be increased to 160%. And, the PWM duty value of LED array applying BPL drive can be reduced to 67% level.

Therefore, the first area value (current * PWM duty) multiplied by the current value of the LED array and the PWM duty value when applying the general local dimming drive, the current value of the LED array multiplied by the PWM duty value when applying the BPL drive Current * PWM duty) The second area value becomes equal. That is, it is possible to prevent the power consumption from being increased by decreasing the PWM duty by the increased current value.

Here, due to the high luminance of the LED array to which the BPL drive is applied, the luminance difference with the dark portion can be recognized. In the present invention, application of smart black is applied to reduce perception of luminance difference.

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

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

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%, the minimum value of the local dimming is applied, The PWM duty can be limited to 30%.

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 65%, the minimum value of the local dimming is applied, The PWM duty of the array can be limited to 25%.

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%, the minimum value of the local dimming is applied, The PWM duty of the array can be limited 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 is applied to one or more LED arrays PWM duty can be limited within the range of 30% to 25%. If 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 the one or more LED arrays to which the minimum value is applied may be limited within a 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 PWM duty of one or more LED arrays applied may be limited to 50%.

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 65%, the minimum value of the local dimming is applied, The PWM duty of the array can be limited to 35%.

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%, the minimum value of the local dimming is applied, The PWM duty of the array can be limited 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 is applied to one or more LED arrays PWM duty can be limited within the range of 50% to 35%. If 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 the one or more LED arrays to which the minimum value is applied may be limited within a range of 35% to 20% have.

The liquid crystal display device 100 of the present invention can improve display quality by applying BPL (Boost Peak Luminance) and Smart Black driving. Further, even when the brightness of the LED array is locally increased in the BPL driving, the power consumption is not increased.

The liquid crystal display device 100 of the present invention can enhance the contrast ratio of the image by raising the brightness of the LED array locally when driving the BPL. In addition, when the BPL is driven, the PWM duty of the LED array to which the minimum value of the local dimming is applied is limited to a predetermined value or more, thereby reducing the detection of the luminance difference between the bright screen and the dark screen.

It will be understood by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within 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:
162:
166: LED drive IC
170: main controller

Claims (13)

A liquid crystal panel in which a plurality of subpixels are arranged;
A plurality of light emitting diode (LED) arrays disposed under the liquid crystal panel;
A main controller for generating first dimming data for global dimming by analyzing an inputted video signal and generating BPL command data for driving BPL (Boost Peak Luminance);
A timing controller for analyzing the video signal to generate second dimming data for local dimming, and outputting the BPL command data and the second dimming data in packet data; And
In the application of the BPL drive, the first dimming data and the second dimming data are supplied to at least one LED array of the plurality of LED arrays within a range in which power consumption is reduced when applying global dimming vs. local dimming And an LED driver for increasing current. The method according to claim 1,
The first area value obtained by multiplying the current value of the LED array by the PWM duty value when the local dimming drive 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 drive is applied, Wherein the current value of the LED array and the PWM duty value are adjusted when the drive is applied. The method according to claim 1,
The maximum current value of the LED array to which the local dimming is applied is set to 100%, and the maximum current value of the LED array to which the BPL drive is applied is set to 160%. The method according to claim 1,
A liquid crystal display device in which a PWM duty value of an LED array to which local dimming is applied is set to 100%, and a PWM duty value of an LED array to which BPL drive is applied is adjusted within a range of 100% to 20%. 5. The method of claim 4,
The LED driver includes:
A mean value, a minimum value and a maximum value of local dimming of the plurality of LED arrays,
And adjusts the PWM duty of one or more LED arrays to which the minimum value of the local dimming is applied according to the 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%
And limits the PWM duty of the one or more LED arrays to which the minimum value of the local dimming is applied to a first value. 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%
The PWM duty of one or more LED arrays to which the minimum value of the local dimming is applied is limited to a second value smaller than the first value. 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%
And limits the PWM duty of the one or more LED arrays to which the minimum value of the local dimming is applied to a third value smaller than the second value. Generating first dimming data for global dimming by analyzing the input video signal, and generating BPL command data for BPL (Boost Peak Luminance) driving;
Analyzing the image signal to generate second dimming data for local dimming, outputting the BPL command data and the second dimming data in packet data and outputting the second dimming data; And
In the application of the BPL drive, the first dimming data and the second dimming data are supplied to at least one LED array of the plurality of LED arrays within a range in which power consumption is reduced when applying global dimming vs. local dimming And increasing a current of the liquid crystal display device. 10. The method of claim 9,
The first area value obtained by multiplying the current value of the LED array by the PWM duty value when the local dimming drive 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 drive is applied, Adjust the current value of the LED array and the PWM duty value when applying the drive,
Wherein the PWM duty is reduced as the maximum current value of the LED array to which the BPL drive is applied is increased. 11. The method of claim 10,
The PWM duty value of the LED array to which the local dimming is applied is set to 100%, and the PWM duty value of the LED array to which the BPL drive is applied is controlled within the range of 100% to 20%
Wherein the PWM duty of the one or more LED arrays to which the minimum value of the local dimming is applied is limited to 30% if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 100%. 12. The method of claim 11,
Wherein if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 65%, the PWM duty of the one or more LED arrays to which the minimum value of the local dimming is applied is limited to 25%. 12. The method of claim 11,
Wherein if the difference between the maximum value of the local dimming and the minimum value of the local dimming is 20%, the PWM duty of the one or more LED arrays to which the minimum value of the local dimming is applied is limited to 20%.

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