KR20090004016A - Backlight unit assembly - Google Patents

Abstract

A backlight unit assembly is provided to equalizing the luminance of a liquid crystal panel block area, and LED block area by performing the luminance dimming which uses the point spread function. A liquid crystal display panel assembly comprises an LCD panel(3000) and an LCD panel driving part(4000) for operating the same. A backlight unit assembly comprises a backlight unit(1000) for supplying the light to the LCD panel and the backlight unit driving part(700) for operating this. An upper and a lower receiving member receives and protects a liquid crystal display panel assembly and a backlight unit assembly. The LCD panel is classified into data line and gate line of the fixed number.

Description

Backlight Unit Assembly {BACKLIGHT UNIT ASSEMBLY}

The present invention relates to a backlight unit assembly, a liquid crystal display including the same, and a dimming method thereof, and more particularly, to a backlight unit assembly implementing a luminance dimming using a jumper function, a liquid crystal display including the same, and a dimming method thereof. .

Recently, flat panel displays such as liquid crystal displays (LCDs) and plasma display panels (PDPs) are rapidly developing in place of cathode ray tubes (CRTs). Among such flat panel display devices, the liquid crystal display device does not have self-luminous light unlike a plasma display device and the like, and requires a light source. In this case, a light source such as a light emitting diode (LED) is generally used as a light source, or a line such as an electroluminescent lamp (EL) or a cold cathode fluorescent lamp (CCFL). Use a light source. Among the light sources, a light emitting diode is recently used as a light source for a backlight unit.

In recent years, interest in local dimming has increased significantly for the purpose of improving contrast ratio (CR) and reducing power consumption, with a focus on the light emitting diode backlight unit. That is, by dividing the entire screen area into a plurality of blocks having a uniform size, the gamma curve distortion caused by the light leakage phenomenon of the panel is corrected through luminance dimming for each block to improve contrast ratio and reduce power consumption.

When local dimming is performed by the luminance dimming method for each block, the individual luminance of the block is extracted by averaging the red, green, and blue image data of each block from the image board. In this case, the block-by-block luminance dimming method does not consider interference light between blocks, and thus there is a problem in that an accurate luminance average value cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a backlight unit assembly capable of implementing luminance dimming in consideration of interference light, a liquid crystal display including the same, and a dimming method thereof.

According to an aspect of the present invention, there is provided a backlight unit assembly for supplying light to a liquid crystal display panel, comprising: a light emitting diode assembly including at least one light emitting diode block region having a plurality of light emitting diodes, an image signal applied to the liquid crystal display panel; A backlight unit assembly comprising a backlight unit driver for controlling the brightness of the LED block region based on a jumper function.

The backlight unit driver may include a brightness controller for determining an average value of the corrected luminance of the light emitting diode block region, and a dimming controller for controlling the brightness of the light emitting diode block region based on the corrected brightness average value determined by the brightness controller. . The average value of the corrected luminance is characterized by subtracting the interference light by the jumper function from the average luminance of the image signal.

The backlight unit driver may further include a memory unit for storing a jump function, the backlight unit driver may include an FPGA, and the luminance controller and the dimming controller may be embedded in the FPGA.

In addition, the present invention may include an optical sensor for measuring the light emitted from the light emitting diode block region. In this case, the optical sensor may include a color sensor capable of measuring red, green, and blue light, and the luminance controller may adjust the luminance of the LED block area by comparing the average value of the corrected luminance with the light measured by the optical sensor. have. The optical sensor can operate continuously or intermittently.

The backlight unit driver may further include a color controller for determining a representative color of the light emitting diode block region. The memory unit may include color class table information including a plurality of color classes including color grayscales of which visibility is close, and color coordinate table table information including a plurality of color gamuts of visibility in a color coordinate system. The color controller is preferably a color region in which the color class of the image signal applied to the liquid crystal display panel is most mapped, and determines the representative color as the color of the light emitting diode block region.

In addition, the present invention may further include an optical sheet for improving the quality of the light emitted from the plurality of light emitting diodes, wherein the optical sensor measures the light reflected from the optical sheet is incident to the liquid crystal display panel Effective in measuring

The light emitting diodes may include white, red, green, and blue light emitting diodes.

The present invention also provides a liquid crystal display panel for displaying an image, a liquid crystal display panel driver for driving the liquid crystal display panel, and at least one light emitting diode having a plurality of light emitting diodes for supplying light to the liquid crystal display panel. And a backlight unit driver for controlling the brightness of the LED block region based on an image signal and a jump function applied to the liquid crystal display panel. To provide.

The liquid crystal display panel may include a plurality of liquid crystal display panel block regions, and the light emitting diode block region may be formed at a position corresponding to the liquid crystal display panel block region.

In addition, the present invention includes the steps of calculating a luminance average value of each pixel data of the liquid crystal display panel block region; Calculating a corrected luminance average value using the luminance average value and the point distribution function; It provides a dimming method of a liquid crystal display device comprising the step of adjusting the luminance of the light emitting diode block region to the average value of the corrected luminance.

In this case, the dimming method comprises the steps of measuring the brightness of the light emitting diode block region with an optical sensor; Calculating a luminance difference value by comparing the measured luminance with the corrected luminance average value; The method may further include adjusting luminance of the LED block region according to the luminance difference value.

The dimming method may further include classifying a color class of pixels of the LCD panel block area; Determining a representative color among the color classes; Adjusting the color of the light emitting diode block region to the representative color; may further include classifying the color class of the pixels of the liquid crystal display panel block region; storing the color class table information in the memory unit; Extracting an image signal of each pixel data of the liquid crystal display panel block region; And classifying a color class by comparing the image signal with color class table information. In this case, storing the color class table information in the memory unit; dividing the red, green, blue by a predetermined color gray scale; Grouping adjacent color gray scales among the color gray scales into one color class; Storing the color class table information in a memory unit by tabulating the color classes. The determining of the representative color among the color classes may include: mapping the color class to a color coordinate system; And determining the color gamut of the color coordinate system to which the color class is most mapped as the representative color. The method may further include: mapping the color class to a color coordinate system; dividing the color coordinate system into a plurality of color regions each having visibility; And mapping the color class to each corresponding color area.

The present invention provides a backlight unit assembly capable of matching luminance of a liquid crystal display panel block area with that of a light emitting diode block area by performing brightness dimming using a jumper function to consider interference light, and a liquid crystal display device including the same. A dimming method can be provided.

The present invention also provides a backlight unit assembly including a backlight unit assembly capable of minimizing a difference in luminance between a light emitting diode block region and a liquid crystal display panel block region by measuring the brightness of the light emitting diode block region using an optical sensor, and a dimming thereof. It may provide a method.

In addition, the present invention performs luminance dimming using a jumper function for color dimming, and corresponds to a corrected luminance average value considering the representative color and interference light of the liquid crystal display panel block region and the color and luminance of the corresponding LED block region. By providing a backlight unit assembly, a liquid crystal display including the same, and a dimming method thereof may be provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like reference numerals in the drawings refer to like elements.

1 is a schematic exploded perspective view of a liquid crystal display according to a first embodiment of the present invention, FIG. 2 is a schematic plan view of a light emitting diode assembly according to a first embodiment of the present invention, and FIG. 3 is a first embodiment of the present invention. 4 is a conceptual diagram illustrating a liquid crystal display average value according to a first embodiment of the present invention, and FIG. 5 is a diagram illustrating luminance dimming of the liquid crystal display device according to the first embodiment of the present invention. This is a flowchart for explaining.

As shown in FIGS. 1 to 3, the liquid crystal display according to the first exemplary embodiment of the present invention includes a liquid crystal display panel assembly including a liquid crystal display panel 3000 and a liquid crystal display panel driver 4000 for driving the liquid crystal display panel 3000. The backlight unit assembly may include a backlight unit 1000 for supplying light to the liquid crystal display panel 3000 and a backlight unit driver 700 for driving the backlight unit 1000. In this case, the display apparatus may further include upper and lower accommodating members 2600 and 400 for accommodating and protecting the liquid crystal display panel assembly and the backlight unit assembly, respectively. In addition, the liquid crystal display panel 3000 according to the present exemplary embodiment may be divided into a plurality of data lines and gate lines, and may be divided into a plurality of liquid crystal display panel block regions A, which are virtual block regions of a matrix form having a predetermined size. In addition, the backlight unit 1000 may also be divided into a plurality of light emitting diode block regions B so as to correspond to the plurality of liquid crystal display panel block regions A.

The liquid crystal display panel assembly includes a thin film transistor substrate 2220, a color filter substrate 2240 corresponding to the thin film transistor substrate 2220, and a liquid crystal layer injected between the thin film transistor substrate 2220 and the color filter substrate 2240. And a liquid crystal display panel driver 4000 for driving the liquid crystal display panel 3000. In this case, the liquid crystal display panel 3000 may further include a polarizer (not shown) formed to correspond to the upper portion of the color filter substrate 2240 and the lower portion of the thin film transistor substrate 2220, respectively.

The color filter substrate 2240 is a substrate in which red (R), green (G), and blue (B) pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process. A common electrode (not shown) made of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO), which is a transparent conductive thin film, is formed on the entire surface of the color filter substrate 2240. It is.

The thin film transistor substrate 2220 is a transparent glass substrate in which a thin film transistor (TFT) and a pixel electrode are formed in a matrix form. The data line is connected to the source terminal of the thin film transistors, and the gate line is connected to the gate terminal. In addition, a pixel electrode (not shown) made of a transparent electrode made of a transparent conductive material is connected to the drain terminal. When an electrical signal is input to the data line and the gate line, each thin film transistor is turned on or turned off to apply an electrical signal necessary for pixel formation to a drain terminal. In this case, the liquid crystal display panel driver 4000 may be provided to apply a signal to the liquid crystal display panel 3000.

The liquid crystal display panel driver 4000 is configured to drive the liquid crystal display panel 3000, and includes a data side and gate side tape carrier packages (TCP) 2260a and 2280a connected to the thin film transistor substrate 2220. And data side and gate side printed circuit boards 2260b and 2280b connected to the data side and gate side tape carrier packages 2260a and 2280a, respectively.

The backlight unit assembly is for supplying light to the liquid crystal display panel 3000, and includes a light emitting diode assembly 300 having a plurality of light emitting diodes and an optical sheet 500 for improving the quality of light emitted from the plurality of light emitting diodes. And a backlight unit 1000 including an optical sensor 320 for measuring light reflected from the optical sheet 500, and a backlight unit driver for driving a plurality of light emitting diodes provided in the light emitting diode assembly 300. 700). In this case, the light emitting diode assembly 300 may further include a mold frame 2000 for fixing the optical sheet 500. In addition, the light emitting diode assembly 300 according to the present embodiment will be described with an example in which a plurality of light emitting diodes are mounted on a substrate.

The light emitting diode is a light source of a backlight unit assembly according to an embodiment of the present invention, a compound semiconductor laminate structure having a pn junction structure, a light emitting chip using a phenomenon of emitting light by recombination of minority carriers (electrons or holes), and a light emitting chip It may include a base member for mounting, and an external power input member for applying external power to the light emitting chip.

The light emitting diode according to the present embodiment implements white by using red (R), green (G), and blue (B) light emitting diodes as one cluster. That is, white is realized by a combination of red (R), green (G), and blue (B) light emitting diodes, and a plurality of such light emitting diode clusters may be provided. In this case, the plurality of light emitting diodes according to the present exemplary embodiment may be individually driven to be driven by a local dimming method.

The red (R), green (G), and blue (B) light emitting diodes are disposed close to each other so that the colors can be mixed, and the arrangement form is preferably a diamond shape or a rectangular shape with respect to the top view. Do. Of course, the arrangement is not limited thereto, and red (R), green (G), and blue (R), green (G), and blue (B) light emitting diodes may be used to properly mix the red (R), green (G), and blue ( B) If the light emitting diodes are arranged as close as possible, the arrangement can be carried out in various ways. At this time, instead of the red (R), green (G), and blue (B) light emitting diodes, the red (R), green (G), and blue (B) light emitting chips, a base member for packaging the same, and red (R), green ( G), a single package including an external power input member for applying external power to the blue (B) light emitting chip may be used. However, the present invention is not limited thereto, and a specific light emitting chip lacking luminance may be further added, for example, a green (G) light emitting chip. Of course, such a configuration may also be packaged in a single package by packaging the corresponding light emitting chip, and may be individually packaged for each light emitting chip. In addition, the present embodiment is not only a light emitting diode that realizes white by mixing red (R), green (G), and blue (B) light, but also other methods, for example, white phosphors using a yellow phosphor on a blue light emitting chip. A light emitting diode may also be used.

The optical sensor 320 measures red, green, and blue light emitted from a light emitting diode. The optical sensor 320 combines a three-channel photodiode with an optical filter of each RGB color to display a visible light region having a wavelength range of 380 nm to 780 nm. It may include an RGB color sensor that can be detected by classifying each of the red, green, and blue color signals. In this case, the optical sensor 320 according to the present exemplary embodiment effectively measures the light reflected from the optical sheet 500 instead of the light emitted from the individual light emitting diodes in order to measure the light incident on the liquid crystal display panel 3000. to be. In addition, the photosensor 320 is effectively formed in the center of each of the plurality of light emitting diode block regions (B). Of course, the present invention is not limited thereto, and the optical sensor 320 may be mounted only at the corners and the center of the LED assembly 300 as shown in FIG. 2. In the present embodiment, the first light sensor 320a and the second to fifth light sensors 320b to 320e are mounted on the corners of the light emitting diode assembly 300, respectively. Let's explain.

The backlight unit driver 700 is used to drive a plurality of light emitting diodes provided in the light emitting diode assembly 300. The backlight unit driver 700 controls the image signals output from the converter 600 that receives an image signal applied from an external video card. A field-programmable gate array (FPGA) 720 for outputting to the display panel 3000 and the backlight unit 1000, and modulation for driving a light emitting diode by a signal applied from the FPGA The unit 740, the LED driver 760, and a power supply unit for supplying power to the LED driver 760 may be included.

The FPGA 720 is for receiving and outputting a signal applied from the converter 600, and coding and decoding of an image signal applied from the converter 600, which is a video board (Analog / Digital Board), and an applied image. Signal timing is controlled by controlling the timing of the signal and applied to the liquid crystal display panel driver and the backlight unit driver, and the luminance information and jumper of the image signals R ', G', B ', and W' DATA applied from the signal distributor. A brightness control unit BC for determining a luminance average value of the light emitting diode block region B based on a point spread function PSF, and outputting a brightness control signal S ₃ according to the brightness control signal S; ₃ ) dimming control including luminance average value information of the image signals R ', G', B ', and W'DATA by receiving and modulating the reference voltage signal applied from the power supply unit (not shown). The dimming control unit DC for outputting the signal S ₂ and the jumper function The memory unit MO may be included. In this case, the brightness control unit BC according to the present exemplary embodiment compares the luminance of the light emitting diode block region B measured by the optical sensor 320 with the corrected luminance average value and accordingly dimming the corrected luminance average value information. DC) may be applied.

The liquid crystal display according to the present exemplary embodiment calculates a luminance average value of the liquid crystal display panel block region A, and shows a luminance of light that is emitted from the center light when the luminance of the center light is 1.00 as shown in FIG. 4. A jump average function of the light intensity distribution function for the light source may be used to calculate a luminance average value of the LED block region B, which is a corrected luminance average value in which the interference light is considered. That is, the corrected luminance average value may be implemented by reducing the luminance of the interference light at the luminance average value of the image signal. In this case, the present embodiment calculates the corrected luminance average value by using a 5x5 jump function.

In the present embodiment, a time controller (T-Con) for controlling timing of an image signal applied to a source driver and a gate driver of the liquid crystal display panel 3000 is separately provided. Although not limited thereto, the time controller may be embedded in the FPGA 720. In addition, the FPGA 720 may also be mounted on a substrate in the form of an integrated circuit (IC).

The power supply unit is for supplying power to the modulator 740 and may include a linear power supply (LPS) or a switch mode power supply (SMPS). In this embodiment, a switching mode power supply, which is advantageous for miniaturization and high efficiency, is used as the power supply unit.

Color and luminance dimming of the liquid crystal display according to the present exemplary embodiment having the above structure is performed by extracting the color and luminance data of each pixel data of the liquid crystal display panel block region A as shown in the flowchart of FIG. 5. (S ₁ ), calculating the luminance average value of each pixel data of the liquid crystal display panel block area A (S ₂ ), calculating the average luminance value by using the luminance average value and the jumper function (S ₃ ), and correcting luminance. Adjusting the brightness of the light emitting diode block area (B) by the average value (S ₄ ), Comparing the measured brightness and the average value of the corrected brightness (S ₅ ), calculating the brightness difference value (S ₅ ), the light emitting diode block according to the brightness difference value In operation S ₆ , the brightness of the region B may be adjusted.

Extracting the color and luminance data of each pixel data of the liquid crystal display panel block region A (S ₁ ) determines a color class by comparing the image signal of the liquid crystal display panel block region A with color class table information. The image signal is extracted from the signal distribution unit and applied to the luminance control unit to obtain the average luminance.

Computing the luminance average value of each pixel data of the liquid crystal display panel block region A (S ₂ ) may be performed by analyzing luminance characteristics in the image signal of each pixel of the extracted liquid crystal display panel block region A. The luminance average value for the entire luminance of the block area A is calculated. That is, the luminance controller calculates a luminance average value by summing the luminance intensities of each pixel in the image signal for each pixel in the applied liquid crystal display panel block region A and dividing it by the number of pixels in the liquid crystal display panel block region A. .

In operation S ₃ , the corrected brightness average value is calculated by reducing the brightness mean value by the amount of interference light calculated using the jumper function to the calculated brightness mean value. At this time, the interference light is light that the brightness of the other liquid crystal display panel block area A positioned around the extracted liquid crystal display panel block area A affects the one liquid crystal display panel block area A. The jumper function can be obtained by substituting the jumper function for the luminance of the other liquid crystal display panel block region A. FIG.

In step S ₄ of adjusting the luminance of the light emitting diode block region B using a correction luminance average value, a dimming control unit DC is applied to a dimming control unit DC by applying a luminance control signal for the correction luminance average value to the dimming control unit DC. The luminance of the area B is adjusted to correspond to the average value of the corrected luminance.

That is, the luminance controller applies the luminance control signal for the corrected luminance average value to the dimming controller DC, and the dimming controller DC applies the dimming control signal to the modulator 740 according to the applied luminance control signal. In addition, the modulator 740 adjusts the duty ratio of the power applied from the power supply unit in a pulse width modulation manner to adjust the luminance of the LED block region B according to the applied dimming control signal. The light emitting diode driver 760 drives the light emitting diode block region B stably according to the applied signal.

Computing the luminance difference value by comparing the measured luminance and the average value of the corrected luminance (S ₅ ) may be implemented by measuring the luminance of the light emitting diode block region B with the optical sensor 320 and comparing it with the corrected luminance average value. .

That is, the photosensor 320 measures the brightness of the light emitting diode block area B and applies a signal thereof to the brightness control unit BC, and the brightness control unit BC controls the brightness of the light emitting diode block area B. A luminance difference value that is a difference between the measured luminance and the corrected luminance average value is calculated by comparing with the average value of the corrected luminance. In addition, the luminance controller BC adjusts the average corrected luminance value based on the calculated luminance difference value, and applies the luminance control signal S ₃ to the dimming controller DC.

At this time, in the present embodiment, the first to fifth optical sensors 320a to 320e are provided at the center and the corner of the light emitting diode assembly 300, respectively. However, when it is difficult to provide the first optical sensor 320a at the center of the LED assembly 300, the first to third sensor 320a provided at the center of the LED assembly 300 is omitted and the second to the second The optical sensor 320 may be configured by only the five optical sensors 320b to 320e. However, when the first optical sensor 320a is omitted, accurate light measurement becomes difficult from the edge of the light emitting diode assembly 300 to the center. Therefore, when the second to fifth optical sensors 320b to 320e are provided only at the edges of the LED assembly 300 as described above, the center of the LED assembly 300 and the second to fifth optical sensors are measured using a measuring device. By measuring the color deviation of the corners (320a ~ 320e) in advance in the database, and using this to predict the brightness of the light emitting diode block area (B) located in the center of the light emitting diode assembly 300 by using only the light measured at the corners You can correct it.

In operation S ₆ of adjusting the luminance of the LED block region B according to the luminance difference value, the dimming control signal S ₂ adjusted by the dimming control unit DC according to the luminance difference value is transmitted to the modulator 740. The modulator 740 adjusts the luminance of the LED block region B to correspond to the luminance difference value according to the applied dimming control signal S ₂ .

In this case, the step of calculating the luminance difference value by comparing the measured luminance and the average value of the corrected luminance (S ₅ ) or adjusting the luminance of the LED block region B according to the luminance difference value (S ₆ ) is continuously performed. Or it may be carried out intermittently.

As described above, the liquid crystal display according to the present exemplary embodiment uses the image signal and the jumper function to determine the luminance of the light emitting diode block region B so that the liquid crystal display panel block region A and the light emitting diode block region B The luminance may be matched. In addition, in the liquid crystal display according to the present exemplary embodiment, the luminance difference between the light emitting diode block region B and the liquid crystal display panel block region A is measured by measuring the luminance of the light emitting diode block region B using the optical sensor 320. Can be minimized.

Next, a liquid crystal display according to a second exemplary embodiment of the present invention will be described with reference to the drawings. Descriptions overlapping descriptions of the liquid crystal display according to the first exemplary embodiment of the present invention will be omitted or briefly described below.

6 is a conceptual diagram of a liquid crystal display according to a second embodiment of the present invention, FIG. 7 is a flowchart illustrating luminance dimming and color dimming of the liquid crystal display according to the second embodiment of the present invention. 9 is a conceptual diagram illustrating a method of separating color information for color dimming of a liquid crystal display according to a second exemplary embodiment of the present invention.

As shown in FIG. 6, the liquid crystal display according to the second exemplary embodiment of the present invention includes a liquid crystal display panel assembly including a liquid crystal display panel 3000 and a liquid crystal display panel driver 4000 for driving the liquid crystal display panel, and a liquid crystal display. The backlight unit includes a backlight unit 1000 for supplying light to the panel 3000 and a backlight unit driver 700 for driving the backlight unit 1000. In this case, the liquid crystal display panel 3000 may be divided into a plurality of liquid crystal display panel block regions A, and the backlight unit 1000 may also have a plurality of light emitting diode block regions B as in the above-described embodiment. Can be divided into In addition, the liquid crystal display panel 3000 and the backlight unit 1000 may be sequentially driven from the same direction, for example, from top to bottom. In this case, the plurality of light emitting diode block regions B may include a plurality of red (R), green (G), and blue (B) light emitting diodes for color dimming, and include red (R), green (G), Blue (B) light emitting diodes may be individually driven. That is, red (R), green (G), and blue (B) light emitting diodes may have different cluster colors by individual driving. In addition, the red, green, and blue LED drivers 760 (760a, 760b, and 760c) for individually driving the red (R), green (G), and blue (B) light emitting diodes may be provided.

The backlight unit driver 700 according to the present exemplary embodiment includes a color controller CC as well as a luminance controller BC and a dimming controller DC to simultaneously perform color dimming and luminance dimming. That is, the backlight unit driver 700 according to the present exemplary embodiment includes the image signals R ', G', B ', and W' DATA applied from the liquid crystal display panel driver 4000 to apply a signal to the liquid crystal display panel 3000. A luminance control unit BC for determining a corrected luminance average value based on luminance information and a jump function and outputting the luminance control signal S ₃ according to the luminance information and the jumper function, and the image signals R ', G', B ', analyzing the color information of the W 'DATA) to determine the representative color on the basis of this, and thereby the color control signal (color control (CC) and said brightness control signal (S ₃₎ and the color control signal for outputting the S ₁₎ in accordance with ( S ₁ ) and modulating the reference voltage signal applied from the power supply unit (not shown) on the basis of this, thereby correcting luminance average value information and representative color of the image signals R ′, G ′, B ′, and W ′ DATA. And a dimming control unit DC for outputting a dimming control signal S ₂ including information.

Here, the luminance control signal S ₃ is a digital signal representing the average of the corrected luminance values of the image signals R ′, G ′, B ′, and W ′ DATA, and the color control signal S ₁ is the image signal R ′. , G ', B', W'DATA) is represented by digital signal. Of course, the image signals R ', G', B ', and W' DATA may include only the red, green, and blue image signals R ', G', and B 'DATA of each pixel as in the above-described embodiment. In this case, the white image signal W'DATA may be obtained using the red, green, and blue image signals R ', G', and B'DATA. That is, the liquid crystal display according to the present exemplary embodiment continuously performs luminance dimming to a luminance average value corrected by using a jumper function on the luminance average value of the liquid crystal display panel block region A using the white image signal W'DATA. Color dimming is continuously or intermittently performed using the red, green, and blue image signals R ', G', and B'DATA. Of course, luminance dimming and color dimming may be performed continuously.

Such color and luminance dimming is performed by storing color class table information in a memory unit as shown in the flowchart of FIG. 7 (S ₁ ), and extracting color and luminance data of each pixel data of the liquid crystal display panel block region A. FIG. (S ₂ ), calculating a luminance average value of each pixel data of the liquid crystal display panel block region A (S ₃ ), calculating a luminance correction average value using a luminance average value and a jumper function (S ₄ ), Classifying a color class of each pixel data of the liquid crystal display panel block region A (S ₅ ), mapping a color class of the liquid crystal display panel block region A to a color coordinate system (S ₆ ), and a liquid crystal display panel Determining a representative color of the block area (A) (S ₇ ), adjusting the brightness of the light emitting diode block area (B) by the corrected luminance average value (S ₈ ), adjusting the color of the LED convex area by the representative color Step (S ₉ ), measurement In operation S ₁₀ , the luminance difference value may be calculated by comparing the averaged luminance and the corrected luminance average value, and the operation S ₁₁ may be performed to adjust the luminance of the LED block region B according to the luminance difference value.

In the storing of the color class table information in the memory unit (S ₁ ), the respective gray levels are divided into a plurality of color classes according to the gamma curve characteristics of the liquid crystal display panel 3000 for each color. At this time, unlike luminance, similar colors are difficult for a person to distinguish. Accordingly, the present exemplary embodiment divides red (R), green (G), and blue (B) into predetermined color gradations, for example, 256 color gradations, each of which is a region of the adjacent region that is difficult for humans to distinguish. Color gradations are defined as a color class. In this embodiment, as shown in FIG. 8, the color gradations divided into 256 gradations are divided into four red, green, and blue color classes, each of which is tied to the same or similar color gradations. Accordingly, in this embodiment, a total of 256 × 256 × 256 gray scales exist, and the color class may be 4 × 4 × 4.

In this embodiment, red (R), green (G), and blue (B) are divided into four color classes (Class1 to Class4, Class_a to Class_d, Class_1α to Class_4δ), but each color class has visibility. Since the same or identical color ranges are defined as one area, the number of color classes of each color can be changed in various ways, the number of color classes for each color can be the same or different, and the size of the divided color classes is also the color. It may vary depending on the gradation. In addition, color class table information, which is information of such color classes, may be stored in advance in the memory unit MO.

Next, extracting the color and luminance image signal of each pixel data of the liquid crystal display panel block region A (S ₂ ) by comparing the image signal of the liquid crystal display panel block region A with the color class table information The image signal is extracted from the signal distributor to determine the color class and obtain the average luminance.

In operation S ₃ , the luminance average value of each pixel data of the liquid crystal display panel block region A is calculated by analyzing luminance characteristics of an image signal of each pixel of the extracted liquid crystal display panel block region A. The luminance average value for the entire luminance of the block area A is calculated. That is, the luminance intensity of each pixel, that is, the intensity of the red (R), green (G), and blue (B) subpixels constituting each pixel is summed in the image signal for each pixel in the liquid crystal display panel block area A. The luminance average value is calculated by dividing this by the number of pixels of the liquid crystal display panel block area A.

Computing the corrected brightness average value by the brightness average value and the jumper function (S ₄ ) calculates the corrected brightness mean value by reducing the brightness mean value by the interference light calculated using the jumper function to the calculated brightness mean value.

In operation S ₄ , the color class of each pixel data of the liquid crystal display panel block area A may be classified by comparing the red, green, and blue image signals of each pixel extracted by the signal distribution unit with the color class table information. Give a color class.

For example, the red (R) gradation among the red (R), green (G), and blue (B) pixel data extracted as shown in FIG. 8 is between steps 127 and 191, and thus is given a red color class of Class3. do. In addition, since the green (G) gradation is between 0 and 63 levels, the green color class of Class_a is given, and since the blue (B) gradation exists between 0 and 63 levels, the blue color class of Class_1α is given. . Accordingly, the pixel is given a color class of Class3a1α. That is, when each pixel data has an adjacent color gradation within a predetermined range, the pixel data is given the same color class.

In the step S ₆ of mapping the color class of the liquid crystal display panel block area A to the color coordinate system, the color classes of the liquid crystal display panel block area A are mapped to the color coordinate system in which the color area is divided in advance. In operation S ₆ of mapping the color class of the liquid crystal display panel block area A to the color coordinate system, the color classes are mapped to the corresponding color class area in the CIE 1976 UCS color coordinate system of FIG. 9. In this case, the color gamut of the color coordinate system defines color gradations having similar visibility as one color gamut, and the color coordinate system may include a plurality of such color gamuts. In addition, the plurality of color gamuts are tabulated, and the color coordinate system table information in which the plurality of color gamuts are tabulated is stored in the memory unit MO in the same manner as the color class table information. In addition, in the above, the red (R), green (G), and blue (B) pixel data input to the liquid crystal display panel block area A is assigned a color class according to the gradation level for each color, and then mapped to the color coordinates. The present invention is not limited thereto, and the color class assignment step may be omitted and directly mapped to the color coordinates. In this case, it is preferable that the color gamut of the color coordinate system is also defined as one color gamut having similar or identical visibility.

In operation S ₇ of determining the representative color of the liquid crystal display panel block area A, the color area of the color coordinate system having the highest value among the color classes mapped to the color coordinate system is determined as the representative color. In this case, the color class is assigned to the red (R), green (G), and blue (B) pixel data input to the liquid crystal display panel block area A according to the gradation level for each color, and then a plurality of color classes are assigned. Although the representative color is determined by mapping to the color coordinates, the present invention is not limited thereto, and the representative color may be determined by mapping one color class having the highest value among the color classes to the color coordinate system.

Dimming the luminance of the light emitting diode block region B with the corrected luminance average value (S ₈ ) may apply a luminance control signal for the corrected luminance average value to the dimming controller DC so that the dimming controller DC may receive the light emitting diode block region ( Adjust the luminance of B) to correspond to the average value of the corrected luminance.

Dimming the color of the LED convex region with the color of the representative color (S ₉ ) by applying a color control signal for the representative color to the dimming controller (DC) so that the dimming controller (DC) of the light emitting diode block region (B) The color is adjusted to be similar to or the same as the representative color of the liquid crystal display panel block area A. FIG.

That is, the step S ₇ of adjusting the brightness of the LED block region B by the luminance average value and the step S ₈ of adjusting the color of the LED convex region by the representative color are the liquid crystal display panel block region A. The luminance control signal S ₃ is applied to the light emitting diode block region B from the luminance control unit BC through the dimming control unit DC, and the color control signal S ₁ for the representative color is applied. The control unit CC is applied to the dimming control unit DC. In addition, the color and luminance of the LED block region B may be reduced by the color control signal S ₁ and the luminance control signal S ₃ applied to the dimming controller DC. To correspond with the representative color and luminance average value. In this case, it is effective to implement such color dimming by individually adjusting the currents of the plurality of red, green, and blue light emitting diodes constituting the corresponding light emitting diode block region (B). It is effective to implement the overall regulation of the diodes.

Computing the luminance difference value by comparing the measured luminance and the average value of the corrected luminance (S ₁₀ ) may transmit a signal for the luminance of the light emitting diode block region B measured by the optical sensor 320 to the luminance controller BC. The luminance control unit BC may be implemented by comparing the average value with the corrected luminance average value. In addition, the luminance controller BC adjusts the average corrected luminance value based on the calculated luminance difference value, and applies the luminance control signal S ₃ to the dimming controller DC.

In operation S ₁₁ of adjusting the luminance of the LED block region B according to the luminance difference value, the dimming control signal S ₂ adjusted by the dimming control unit DC according to the luminance difference value is transmitted to the modulator 740. The modulator 740 adjusts the luminance of the light emitting diode block region B to correspond to the luminance difference value according to the applied dimming control signal S ₂ .

As described above, the liquid crystal display according to the present exemplary embodiment performs luminance dimming using a jumper function for color dimming, so that the average luminance and the corrected luminance value considering the representative color and the interference light of the liquid crystal display panel block region A and the corresponding The color reproducibility can be improved by matching the color and luminance of the LED block region B.

Although described above with reference to the drawings and embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit of the invention described in the claims below. I can understand.

1 is a schematic exploded perspective view of a liquid crystal display according to a first embodiment of the present invention.

2 is a schematic plan view of a light emitting diode assembly according to a first embodiment of the present invention;

3 is a conceptual diagram of a liquid crystal display according to a first embodiment of the present invention.

4 is a conceptual diagram illustrating a correction luminance average value according to the first embodiment of the present invention.

5 is a flowchart illustrating luminance dimming of the liquid crystal display according to the first exemplary embodiment of the present invention.

6 is a conceptual diagram of a liquid crystal display according to a second embodiment of the present invention.

7 is a flowchart illustrating luminance dimming and color dimming of the liquid crystal display according to the second exemplary embodiment of the present invention.

8 and 9 are conceptual views illustrating a method of separating color information for color dimming of a liquid crystal display according to a second exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

320: light sensor 600: conversion unit

700: backlight unit driver 720: FPGA

740: modulator 760: light emitting diode driver

1000: backlight unit 3000: liquid crystal display panel

4000: liquid crystal display panel driver A: liquid crystal display panel block area

B: light emitting diode block area BC: luminance control part

CC: color control unit DC: dimming control unit

Claims (1)

A backlight unit assembly for supplying light to a liquid crystal display panel, A light emitting diode assembly comprising at least one light emitting diode block region having a plurality of light emitting diodes; And a backlight unit driver for controlling luminance of the light emitting diode block area based on an image signal and a jump function applied to the liquid crystal display panel.

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