KR101327835B1 - Driving circuit for liquid crystal display device and method for driving the same - Google Patents

Driving circuit for liquid crystal display device and method for driving the same Download PDF

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Publication number
KR101327835B1
KR101327835B1 KR1020060136850A KR20060136850A KR101327835B1 KR 101327835 B1 KR101327835 B1 KR 101327835B1 KR 1020060136850 A KR1020060136850 A KR 1020060136850A KR 20060136850 A KR20060136850 A KR 20060136850A KR 101327835 B1 KR101327835 B1 KR 101327835B1
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KR
South Korea
Prior art keywords
backlight
luminance
driving
plurality
liquid crystal
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KR1020060136850A
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Korean (ko)
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KR20080061771A (en
Inventor
주학림
홍희정
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엘지디스플레이 주식회사
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Priority to KR1020060136850A priority Critical patent/KR101327835B1/en
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    • GPHYSICS
    • G02OPTICS
    • G02FDEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating, or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating, or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating, or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336Illuminating devices
    • G02F1/133602Direct backlight
    • G02F1/133603Direct backlight with LEDs
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406Control of illumination source
    • G09G3/3413Details of control of colour illumination sources
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21YINDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00Light-generating elements of semiconductor light sources
    • F21Y2115/10Light-emitting diodes [LED]

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device and a driving method of a liquid crystal display device capable of improving color gamut of a liquid crystal panel while reducing power consumption of a backlight by controlling LED driving according to image data. A liquid crystal panel provided; A data analyzer for dividing the input image data into a plurality of regions and converting and generating a pulse width modulated signal according to the divided image data; A backlight for irradiating light onto the liquid crystal panel; And a backlight controller configured to generate a backlight driving signal according to the converted pulse width modulation signal to drive the backlight for each of the divided regions.
Image Partition, LED Backlight Split Drive, Pulse Width Modulation (PWM) Signal

Description

Driving device for liquid crystal display and driving method thereof {Driving circuit for liquid crystal display device and method for driving the same}

1 is a block diagram showing a driving device of a liquid crystal display according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the data analysis unit shown in FIG. 1. FIG.

3A illustrates an input image.

3B is a diagram illustrating a divided region of a backlight.

4A to 4C are waveform diagrams showing PWM signals for driving the P1, P4 and P7 regions shown in FIG. 3B.

5A to 5C are other waveform diagrams showing PWM signals for driving the P1, P4 and P7 regions shown in FIG. 3B.

* Description of symbols for main parts of the drawings *

10: data analysis unit 12: backlight control unit

14: backlight 22: video divider

24: luminance analyzer 26: PWM signal generator

RGBS: Split image data PWMS: Converted pulse width modulated signal

P1 to P20: first to twentieth divided regions

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to drive and drive a liquid crystal display device capable of improving color gamut of a liquid crystal panel while reducing power consumption of a backlight by controlling LED driving according to image data. It is about a method.

Recently, liquid crystal displays, field emission displays, plasma display panels, and light emitting displays are emerging as flat panel displays.

In general, a liquid crystal display includes a backlight unit by a liquid crystal panel including a plurality of liquid crystal cells arranged in a matrix and a plurality of control switches for switching data signals to be supplied to each of the liquid crystal cells. ), The amount of light transmitted is adjusted to display a desired image on the screen. Specifically, a liquid crystal display device obtains a desired image by forming an electric field in a liquid crystal layer according to a data signal to adjust transmittance of light passing through the liquid crystal layer.

The liquid crystal display includes a liquid crystal panel in which one unit pixel is arranged in a matrix form with three color dots of red (R), green (G), and blue (B). The liquid crystal display combines red, green, and blue light from three color dots of red (R), green (G), and blue (B) passing through the liquid crystal panel to realize one color image. do.

As the backlight unit is miniaturized, thinned, and lightweight, a backlight unit using a light emitting diode (LED), which is advantageous in power consumption, weight, and brightness, has been proposed instead of a fluorescent lamp. As such, the backlight unit using the LED may emit red light, green light, and blue light by using red (R), green (G), and blue (B) LEDs to irradiate the white light to the liquid crystal panel.

However, a backlight unit using a conventional LED always generates red light, green light and blue light at a constant brightness. In addition, since the red light, the green light, and the blue light are always combined in a constant ratio to generate white light having a constant brightness, power consumption increases accordingly. In fact, since the backlight unit occupies most of the power consumed when driving the liquid crystal display, it is necessary to reduce the power consumption of the backlight unit in order to reduce the power consumption of the liquid crystal display.

The present invention is to solve the above problems, the liquid crystal display device and its driving device and driving method which can increase the color reproduction rate of the liquid crystal panel while reducing the power consumption of the backlight unit by controlling the LED driving according to the image data The purpose is to provide.

In order to achieve the above object, a driving apparatus of a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel having a pixel area; A data analyzer for dividing the input image data into a plurality of regions and converting and generating a pulse width modulated signal according to the divided image data; A backlight for irradiating light onto the liquid crystal panel; And a backlight controller configured to generate a backlight driving signal according to the converted pulse width modulation signal and to drive the backlight by the constant current for each of the divided regions.

The data analysis unit divides the input image data into the plurality of regions, and analyzes a luminance ratio of each of the red (R), green (G), and blue (B) data of each of the divided regions, and analyzes the result. And a PWM signal generator for converting a pulse width modulated signal according to the luminance control signal and supplying the luminance control signal to the backlight controller.

The plurality of partitions may correspond to a region for independently driving the backlight by dividing the backlight into a plurality of driving regions.

The PWM signal generation unit compares and analyzes the composition ratios of the red (R), green (G), and blue (B) data of each of the divided regions, and calculates the luminance values of the remaining colors based on the luminance value of the color having the highest composition ratio. To convert the pulse width modulated signal to reduce the maximum to 0%.

In addition, the driving method of the liquid crystal display according to the embodiment of the present invention for achieving the above object comprises the steps of: dividing the input image data into a plurality of areas; Converting and generating a pulse width modulated signal according to each of the divided image data; Generating a backlight driving signal according to the converted pulse width modulation signal; And driving the backlight for each of the divided regions.

The dividing of the image data may include dividing and arranging the input image data according to each division area; And outputting the aligned image data according to each of the divided regions.

Hereinafter, a driving apparatus and a driving method thereof of a liquid crystal display according to an exemplary embodiment of the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a driving apparatus of a liquid crystal display according to an embodiment of the present invention.

The driving apparatus of the liquid crystal display shown in FIG. 1 includes a liquid crystal panel 2 having a pixel region, a data driver 4 driving a plurality of data lines DL1 to DLm, and a plurality of gate lines GL1 to GLn. The gate driver 6 for driving the < RTI ID = 0.0 > 6 < / RTI > and input image data RGB according to a plurality of driving regions and pulse width modulation (PWM) signals (PWMS) The data analyzer 10 converts and generates the divided image data SRGB from the data analyzer 10, supplies the divided image data SRGB to the data driver 4, and supplies the data driver 4 and the gate driver 6. The backlight driving signal BCS is generated by the timing controller 8 controlling the backlight, the backlight 14 irradiating light to the liquid crystal panel 2, and the converted PWM signal PWMS from the data analyzer 10. A backlight controller for driving the light 14 ( 12).

The liquid crystal panel 2 includes a thin film transistor (TFT) formed in each pixel region defined by a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm, and a liquid crystal connected to a TFT. Capacitor Clc is provided. The liquid crystal capacitor Clc is composed of a pixel electrode connected to the TFT and a common electrode facing each other with the pixel electrode and the liquid crystal interposed therebetween. The TFT supplies the data signals from the respective data lines DL1 to DLm to the pixel electrodes in response to the scan pulses from the respective gate lines GL1 to GLn. The liquid crystal capacitor Clc charges the difference voltage between the data signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusts the light transmittance by varying the arrangement of liquid crystal molecules according to the difference voltage. The storage capacitor Cst is connected to the liquid crystal capacitor Clc in parallel so that the voltage charged in the liquid crystal capacitor Clc is maintained until the next data signal is supplied. The storage capacitor Cst is formed by overlapping the pixel electrode with the previous gate line and the insulating layer interposed therebetween. In contrast, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line and the insulating layer interposed therebetween.

In the liquid crystal panel 2, red (R), green (G), and blue (B) pixels are repeatedly arranged in the row / column direction. Here, a separate color filter is not disposed in the red (R), green (G), and blue (B) pixels. The red (R), green (G), and blue (B) pixels form a stripe structure with the same area ratio or different area ratio. Alternatively, each pixel may be arranged in the form of a 2 × 2 matrix.

The data driver 4 converts the digital image data Data into analog image data according to the data control signal DCS from the timing controller 8, and one horizontal period in which scan pulses are supplied to the gate lines GL1 to GLn. Each horizontal analog video data for one horizontal line is supplied to the data lines DL1 to DLm. In other words, the data driver 4 selects a gamma voltage having a predetermined level according to the gray value of the analog image data and supplies the selected gamma voltage to the data lines DL1 to DLm.

The gate driver 6 sequentially generates scan pulses, for example, gate high pulses, and supplies them to the gate lines GL1 to GLn in response to the gate control signal GCS from the timing controller 8.

The timing controller 8 aligns the image data RGBS divided into the plurality of areas from the data analyzer 10 to the data driver 4 to be aligned with the driving of the liquid crystal panel 2. In addition, the gate control signal GCS and the data control signal DCS are generated using the synchronization signals DCLK, DE, Hsync, and Vsync from the outside to control the data driver 4 and the gate driver 6. .

The data analyzer 10 divides the image data RGB supplied to each of the unit pixels including red (R), green (G), and blue (B) subpixels according to a plurality of preset division areas. Here, the plurality of divided areas may be preset by the user as an area for dividing and driving the backlight 14 into a plurality of areas. The data analyzer 10 analyzes the luminance ratio of each of the red (R), green (G), and blue (B) data of each divided region, converts the PWM signal (PWMS) according to the analyzed result. Create The data analyzer 10 may be embedded in the timing controller 8. A detailed description of the division process of the image data RGB and the conversion of the PWM signal PWMS according to the divided region will be described later with reference to FIGS. 2 to 5.

The backlight controller 12 generates a backlight control signal BCS in response to the converted PWM signal PWMS. In detail, the backlight controller 12 generates the backlight control signal BCS in which the dimming value is modulated according to the PWM signal PWM from the data analyzer 10. Here, the backlight control signal BCS is a control signal that makes the current flowing in the LED constant for uniform light irradiation, and makes the current flowing in the LED constant by adjusting the voltage across the LED. The backlight 14 is driven in a burst mode that varies the LED on / off time of each region according to the backlight control signal BCS while a current flows through both LEDs. In this case, the backlight controller 12 may adjust the brightness of the backlight 14 by varying the on / off time of the LED or the voltage level of the backlight control signal BCS.

Here, the backlight controller 12 may be configured in plural to correspond to the number of the divided regions to independently drive the divided regions of the backlight 12. In this case, the plurality of backlight controllers 12 are independently supplied with the PWM signal PWMS according to each divided region of the backlight 12. Then, the backlight 14 is independently driven for each of the divided regions according to the independently supplied PWM signal PWMS.

The backlight 14 is an LED array (not shown) including a plurality of LED groups composed of three-color LEDs, and disposed on the LED array to improve brightness and efficiency of light from the LED array and irradiate the liquid crystal panel 2. A plurality of optical sheets (not shown) are provided. Each of the plurality of LED groups is disposed in a matrix form on a printed circuit board so that light is uniformly radiated onto the entire rear surface of the liquid crystal panel 2. Many LED groups have a red LED generating red (R) light, a green LED generating green (G) light, and a blue LED generating blue (B) light. In addition, the plurality of optical sheets convert at least one diffuser sheet (or diffuser plate) for diffusing light incident from the LED array, and convert light paths so that the light diffused by the diffuser sheet is directed toward the liquid crystal panel 2. At least one prism sheet that improves efficiency.

The backlight 14 may be driven by being divided into a plurality of areas according to the backlight driving signal BCS. In other words, the backlight 14 has an LED array area of 2 × 3, 2 × 3, 2 × 4, 2 × 5, 3 × 3, 3 × 4, 4 × 4, according to the backlight driving signal BCS. The drive may be divided into configurable areas such as 4 × 5, 5 × 4, 5 × 5, and 6 × 6. The divided regions of the backlight 14 and the driving method of each divided region will be described later in more detail with reference to the accompanying drawings.

FIG. 2 is a diagram illustrating a data analyzer shown in FIG. 1. 3A is a diagram illustrating an input image, and FIG. 3B is a diagram illustrating a divided region of a backlight.

The data analyzer 10 illustrated in FIG. 2 divides the input image data RGB according to the plurality of partitions P1 to P20, and the red of each of the partitions P1 to P20. The luminance analyzer 24 analyzes the luminance ratio of each of the (R), green (G), and blue (B) data and generates the luminance control signal YS according to the analysis result, and the PWM according to the luminance control signal YS. And a PWM signal generator 26 which converts the signal PWMS and supplies it to the backlight controller 12.

The image divider 22 receives image data RGB every frame. 3A, the input image data RGB is divided into a plurality of regions P1 to P20 and arranged as shown in FIG. 3B. Thereafter, the divided image data SRGB of each of the regions P1 to P20 is supplied to the timing controller 8 and the luminance analyzer 24. Meanwhile, the divided regions P1 to P20 illustrated in FIG. 3B are used to independently drive the backlight 14 by dividing the backlight 14 into a plurality of regions. Each of the divided regions P1 to P20 may be set to 4 × 4, 4 × 5, 5 × 4, 5 × 5, 6 × 6, etc. according to the size of the liquid crystal panel 2, but according to the present invention, Only the case where the division areas P1 to P20 are set to 4x5 will be described.

The luminance analyzer 24 analyzes the luminance ratio of each of the red (R), green (G), and blue (B) data of each of the divided regions P1 to P20. Specifically, the luminance analyzer 24 detects luminance of each of the red (R), green (G), and blue (B) data in units of each of the divided regions P1 to P20. In this case, the luminance detection of each of the red (R), green (G), and blue (B) data is performed by the luminance of each of the red (R), green (G), and blue (B) data in units of each of the divided regions (P1 to P20). Is detected to calculate a histogram, and the luminance values of the red (R), green (G), and blue (B) data may be analyzed according to the calculated histogram. As a result of the analysis, for example, the luminance control signal YS is generated according to the luminance values of each of red (R), green (G), and blue (B). Here, the luminance control signal YS may represent the highest luminance value among the luminance values of the red (R), the green (G), and the blue (B), or each of the red (R), the green (G), and the blue (Blue). The average luminance value of (B) may be shown. The luminance control signal YS may be used as a control signal for independently driving the LED array of the backlight 14 according to the plurality of partitions P1 to P20.

The PWM signal generator 26 is generated by converting a PWM signal PWM for driving the LEDs of the red, green, and blue colors B according to the luminance control signal YS. Here, the PWM signal PWMS is a signal for controlling the brightness of each LED and also controls the brightness of the LED by controlling the on-off time. To this end, the PWM signal generation unit 26 analyzes the luminance control signals YS of red (R), green (G), and blue (B) to determine among red (R), green (G), and blue (B). Detects the color with the highest luminance. Here, the color having the highest luminance may mean the color that is most dominant in each of the divided regions P1 to P20.

The PWM signal generator 26 generates a PWM signal PWM so that the luminance of another color can be reduced based on the luminance value of the color having the highest luminance. In other words, the PWM signal generator 26 converts the PWM signal PWM to reduce the LED on time of other colors based on the LED on time of the most dominant color, and converts the PWM signal to the backlight controller 12. Supply.

4A to 4C are waveform diagrams illustrating PWM signals for driving the P1, P4, and P7 regions shown in FIG. 3B.

Specifically, FIGS. 4A to 4C illustrate the LED array using 40% duty ratio red (R), 50% duty ratio green (G) and 70% duty ratio blue (B). A method of setting light to white and adjusting luminance of each color based on the set white (W) is shown.

The first partition P1 illustrated in FIG. 4A is a purple color area. In this case, the PWM signal PWMS of the first partition P1 may be configured to determine the duty ratio of red (R) and green (G) based on the duty ratio of the most dominant color, that is, the blue (B) having the highest luminance. Decrease. For example, the luminance control signal YS of the first divided area P1 input to the PWM signal generator 26 is 40% for red (R) and 10 for green (G) in one frame unit (1Fn). % And blue (B) may be supplied at a duty ratio of 70%. At this time, the PWM signal generator 26 according to the present invention maintains 70% of the blue (B) having the highest luminance value and based on this, the duty ratio of red (R) and green (G) to 10%, respectively Reduced. In this case, the duty ratio of red (R) and green (G) may be reduced to a maximum of 0% based on the blue (B) duty ratio of the highest luminance.

In addition, the PWM signal PWMS of the fourth divided region P4 illustrated in FIG. 4B reduces the duty ratio of blue (B) and green (G) based on the red (R) duty ratio of the highest luminance. Specifically, the luminance control signal YS of the fourth divided area P4 input to the PWM signal generator 26 is 40% red (R) and green (G) and blue (1Fn) in one frame unit (1Fn). B) can each be supplied at a duty ratio of 10% to indicate red color. However, the PWM signal generator 26 reduces the duty ratio of blue (B) and green (G) to 0% based on 40% of red (R) having the highest luminance. Accordingly, the duty ratio of blue (B) and green (G) in the fourth divided region P4 is reduced to a maximum of 0% based on the red (R) duty ratio of the highest luminance, thereby reducing the red color of pure color (R). Will be reproduced.

The PWM signal PWMS of the seventh partition P7 illustrated in FIG. 4C reduces the duty ratios of blue (B) and green (G) by 10% based on the red (R) duty ratio of the highest luminance. Let's do it. Specifically, the luminance control signal YS of the seventh divided region P7 input to the PWM signal generator 26 has 40% of red (R), green (G), and blue (1Fn) in one frame unit. B) can be supplied at a duty ratio of 20% and 10%, respectively, to indicate orange. At this time, the PWM signal generator 26 maintains 40% of the highest luminance red (R) as a reference and reduces the duty ratio of blue (B) and green (G) to 10% and 0%, respectively. . Accordingly, the duty ratio of blue (B) and green (G) in the seventh partition P7 is reduced to a maximum of 0% based on the red (R) duty ratio of the highest luminance to red (R) rather than orange. Near colors can be reproduced.

5A to 5C are waveform diagrams illustrating PWM signals for driving the P1, P4, and P7 regions shown in FIG. 3B.

Specifically, FIGS. 5A to 5C illustrate a method of adjusting the color luminance of the LED array to correspond to the luminance value of the image data RGB without setting the LED array to white (W).

The PWM signal PWMS of the first partition P1 illustrated in FIG. 5A reduces the duty ratio of red (R) and green (G) based on the blue (B) duty ratio of the highest luminance. Specifically, the luminance control signal YS of the first divided area P1 input to the PWM signal generator 26 is 50% of red (R) and 10% of green (G) in one frame unit (1Fn). Blue (B) is supplied at a duty ratio of 60% to display purple. However, the PWM signal generator 26 of the present invention reduces the duty ratio of red (R) and green (G) to 10% and 0%, respectively, based on 60% of blue (B) having the highest luminance. . In this case, the duty ratio of red (R) and green (G) may be reduced to a maximum of 0% based on the blue (B) duty ratio of the highest luminance. Accordingly, in the first divided region P1, a color closer to blue B may be reproduced than purple.

The PWM signal PWMS of the fourth divided region P4 shown in FIG. 5B reduces the duty ratio of blue (B) and green (G) based on the red (R) duty ratio of the highest luminance. Specifically, the luminance control signal YS of the fourth divided area P4 input to the PWM signal generator 26 has 60% of red (R), green (G), and blue (1Fn) in one frame unit (1Fn). B) are each supplied at a duty ratio of 10% to indicate red color. However, the PWM signal generator 26 reduces the duty ratio of blue (B) and green (G) to 0% based on 60% of red (R) having the highest luminance. Accordingly, the duty ratio of blue (B) and green (G) in the fourth divided region P4 is reduced to a maximum of 0% based on the red (R) duty ratio of the highest luminance, thereby reducing the red color of pure color (R). Will be reproduced.

The PWM signal PWMS of the seventh partition P7 illustrated in FIG. 5C reduces the duty ratios of blue (B) and green (G) by 10% based on the red (R) duty ratio of the highest luminance. Let's do it. Specifically, the luminance control signal YS of the seventh divided region P7 input to the PWM signal generator 26 has 50% of red (R), green (G), and blue (1Fn) in one frame unit. B) is supplied at a duty ratio of 20% and 10%, respectively, to indicate orange. However, the PWM signal generator 26 reduces the duty ratios of blue (B) and green (G) to 10% and 0%, respectively, based on 50% of the red (R) having the highest luminance. Accordingly, the duty ratio of blue (B) and green (G) in the seventh partition P7 is reduced to a maximum of 0% based on the red (R) duty ratio of the highest luminance, so that red (R) rather than orange is reduced. It will reproduce colors closer.

As described above, the driving apparatus of the liquid crystal display according to the exemplary embodiment of the present invention divides the input image data RGB according to the divided driving regions P1 to P20 of the backlight 14. The maximum luminance ratio of the divided image data RGBS is calculated and the luminance of the remaining image data is reduced based on the highest luminance data. Accordingly, luminance components that do not significantly affect the image quality of each of the divided regions P1 to P20 may be removed to reduce power consumption when driving the backlight 14. In addition, by dividing the backlight 14 into a plurality of divided regions P1 to P20 and driving them independently according to the divided image data RGBS, color reproducibility may be improved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

As described above, the driving apparatus and driving method of the liquid crystal display according to the exemplary embodiment of the present invention can reduce the power consumption when driving the backlight by removing luminance components having no significant effect on the image quality of each divided region.

In addition, the color reproduction may be improved by dividing the backlight into a plurality of divided regions and driving them independently according to the divided image data.

Claims (18)

  1. A liquid crystal panel having a pixel region;
    A data analyzer for dividing the input image data into a plurality of regions and converting and generating a pulse width modulated signal according to the divided image data;
    A backlight for irradiating light onto the liquid crystal panel; And
    A backlight controller configured to generate a backlight driving signal according to the converted pulse width modulation signal to drive the backlight for each of the divided regions;
    The data analysis unit
    An image divider dividing the input image data into the plurality of regions;
    A luminance analyzer analyzing the luminance ratio of each of the red, green, and blue data of each of the divided regions and generating a luminance control signal according to an analysis result;
    And a PWM signal generator for converting a pulse width modulated signal according to the luminance control signal and supplying the pulse width modulated signal to the backlight controller.
  2. delete
  3. The method of claim 1,
    The image divider
    And dividing the input image data according to the respective divided regions, and outputting the divided image data according to the divided regions.
  4. The method of claim 3, wherein
    The plurality of partitions
    The backlight is divided into a plurality of driving regions and corresponds to a region for driving independently, which is 2 × 3, 2 × 3, 2 × 4, 2 × 5, 3 × 3, 3 × 4, 4 × 4, 4 ×. 5, 5x4, 5x5, and 6x6, wherein the configurable area is set to a drive device for a liquid crystal display device.
  5. 5. The method of claim 4,
    The luminance analyzer
    The luminance of the red (R), green (G) and blue (B) data of each divided area is detected to calculate a histogram and generate a luminance control signal according to the calculated luminance value. Drive system.
  6. 6. The method of claim 5,
    The luminance control signal is
    And a control signal for independently driving the plurality of divided regions using luminance values of red (R), green (G), and blue (B) data of each of the plurality of divided regions. .
  7. The method of claim 6,
    The PWM signal generator
    A pulse width modulated signal is converted to reduce the luminance value of the remaining colors up to 0% based on the highest luminance value among the luminance values of the red (R), green (G), and blue (B) data. Driving device of the liquid crystal display device.
  8. The method of claim 1,
    The backlight is
    LED array including a plurality of LED group consisting of the LED of the red (R), green (G) and blue (B), and
    And a plurality of optical sheets disposed on the LED array to improve brightness and efficiency of light from the LED array and irradiate the liquid crystal panel.
  9. 9. The method of claim 8,
    Backlight control unit
    And generating a backlight control signal in which a dimming value is modulated according to the converted pulse width modulation signal to drive the LED array according to the plurality of divided regions in a burst mode. Drive of the device.
  10. The method of claim 9,
    The backlight control unit
    And a plurality of pixels configured to correspond to the number of the divided regions to drive the backlight independently for each of the divided regions.
  11. Dividing the input image data into a plurality of areas;
    Converting and generating a pulse width modulated signal according to each of the divided image data;
    Generating a backlight driving signal according to the converted pulse width modulation signal; And
    Driving a backlight for each of the divided regions;
    Converting the pulse width modulated signal
    Analyzing a luminance ratio of each of the red, green, and blue data of each of the divided regions and generating a luminance control signal according to an analysis result; and
    And converting a pulse width modulated signal according to the brightness control signal.
  12. The method of claim 11,
    The step of dividing the image data
    Dividing and sorting the input image data according to each of the divided regions; and
    And outputting the aligned image data according to each of the divided regions.
  13. delete
  14. 13. The method of claim 12,
    The plurality of partitions
    The backlight is divided into a plurality of driving regions and corresponds to a region for independently driving, which is set to any one of 4 × 4, 4 × 5, 5 × 4, 5 × 5, and 6 × 6. A method of driving a liquid crystal display device.
  15. 15. The method of claim 14,
    Generating the brightness control signal
    Detecting luminance of red (R), green (G), and blue (B) data of each of the divided regions;
    Calculating a histogram according to the detected luminance, and
    And generating a luminance control signal according to the histogram.
  16. 16. The method of claim 15,
    The luminance control signal is
    And a control signal for independently driving the plurality of divided regions using luminance values of red (R), green (G), and blue (B) data of each of the plurality of divided regions. .
  17. 17. The method of claim 16,
    Converting the pulse width modulated signal
    And a luminance value of the remaining colors is reduced to a maximum of 0% based on the highest luminance value among the luminance values of the red (R), green (G), and blue (B) data.
  18. 18. The method of claim 17,
    Generating the backlight driving signal
    And generating a backlight control signal in which a dimming value is modulated according to the converted pulse width modulation signal.
KR1020060136850A 2006-12-28 2006-12-28 Driving circuit for liquid crystal display device and method for driving the same KR101327835B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9995962B2 (en) 2015-06-12 2018-06-12 Samsung Display Co., Ltd. Backlight unit and display apparatus including the same

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101460696B1 (en) * 2008-07-11 2014-11-21 삼성디스플레이 주식회사 Liquid crystal display and driving method of the same
JP4968219B2 (en) * 2008-09-18 2012-07-04 株式会社Jvcケンウッド Liquid crystal display device and video display method used therefor
KR101674678B1 (en) * 2009-06-30 2016-11-09 엘지이노텍 주식회사 Flat display device and operating method thereof
KR101025800B1 (en) * 2009-07-06 2011-04-04 주식회사 티엘아이 Display device capable of using both of global dimming and local dimming
KR101676245B1 (en) * 2009-12-31 2016-11-15 엘지디스플레이 주식회사 Liquid crystal display device and driving method thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000321571A (en) 1999-05-10 2000-11-24 Nec Viewtechnology Ltd Liquid crystal display device and backlight luminances adjusting method
KR20050104889A (en) * 2004-04-30 2005-11-03 엘지.필립스 엘시디 주식회사 Method and apparatus of driving liquid crystal display
KR20050112952A (en) * 2004-05-28 2005-12-01 엘지.필립스 엘시디 주식회사 Apparatus and method for driving liquid crystal display device
KR100619627B1 (en) 2004-05-27 2006-09-08 엘지.필립스 엘시디 주식회사 Apparatus and method for luminance control of liquid crystal display device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000321571A (en) 1999-05-10 2000-11-24 Nec Viewtechnology Ltd Liquid crystal display device and backlight luminances adjusting method
KR20050104889A (en) * 2004-04-30 2005-11-03 엘지.필립스 엘시디 주식회사 Method and apparatus of driving liquid crystal display
KR100619627B1 (en) 2004-05-27 2006-09-08 엘지.필립스 엘시디 주식회사 Apparatus and method for luminance control of liquid crystal display device
KR20050112952A (en) * 2004-05-28 2005-12-01 엘지.필립스 엘시디 주식회사 Apparatus and method for driving liquid crystal display device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9995962B2 (en) 2015-06-12 2018-06-12 Samsung Display Co., Ltd. Backlight unit and display apparatus including the same

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