KR100653067B1 - Display device and control method thereof - Google Patents

Abstract

A display device and a control method thereof are provided to display a clear image by applying an image signal only to a specific sub pixel with high intensity as the color of a sub pixel receiving zero voltage is not displayed. A display device includes an image signal converting unit(100) for converting an image signal received from the outside into RGB(Red,Green,Blue) and CMY(Cyan,Magenta,Yellow) image signals; a plurality of pixel regions(330) having RGB sub pixels(331,332,333) and CMY sub pixels(334,335,336); a driving circuit unit applying a driving signal to the pixel region; and a control unit(250) for judging an image mode of the received image signal by detecting color intensity of the converted image signal and controlling the driving circuit unit to apply black voltage to one of the RGB and CMY sub pixels on the basis of the judged image mode.

Description

DISPLAY DEVICE AND CONTROL METHOD THEREOF}

1 is a schematic diagram of a display device according to an embodiment of the present invention;

2A and 2B illustrate subpixels for an image mode according to an embodiment of the present invention.

3 is a control flowchart illustrating a control method of a display apparatus according to an exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: image signal conversion unit 200: driving circuit unit

210: gate driver 220: data driver

230: driving voltage generator 240: gray voltage generator

250: control unit 300: thin film transistor substrate

330: Pixel area 331, 332, 333: RGB subpixel

334, 335, 336: CMY subpixel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display apparatus and a control method thereof, and more particularly, to a display apparatus provided with six colors of pixels and a control method thereof.

Recently, a flat panel display such as a liquid crystal display (LCD), a plasma display panel (PDP), or an organic light emitting diode (OLED) has been developed in place of the conventional CRT.

The liquid crystal display device includes a thin film transistor substrate, a color filter substrate, and a liquid crystal display panel in which liquid crystal is injected between both substrates. Since the liquid crystal display panel is a non-light emitting device, a backlight unit for supplying light is disposed on the rear surface of the thin film transistor substrate. Light transmitted from the backlight unit is adjusted according to the arrangement of the liquid crystals. The liquid crystal display panel and the backlight unit are housed in the chassis.

As such, the liquid crystal display includes a thin film transistor and a pixel electrode for applying a voltage transferred from the thin film transistor, and generally displays an image using three primary colors of red, green, and blue. Displaying an image using only the three primary colors of red, green, and blue restricts the color representation of the complementary colors of the three primary colors, and causes poor color reproducibility. In order to improve this, in addition to red, green, and blue, six colors of pixels further including cyan, magenta, and yellow, which are complementary colors of red, green, and blue, are used.

The display device receives various video signals with strong primary colors such as nature or strong intermediate colors such as human skin color. However, the use of six colors of pixels in these various video signals collectively has limitations in reproducing a practical image. .

Accordingly, it is an object of the present invention to provide a display device with improved color reproducibility and a control method thereof.

According to the present invention, there is provided a video signal conversion unit for converting a video signal received from the outside into a video signal of RGB and CMY; A plurality of pixel regions including RGB and CMY subpixels; A driving circuit unit applying a driving signal to the pixel region; Detecting the color intensity of the converted video signal to determine a video mode of the received video signal, and controlling the driving circuit unit to apply a black voltage to any one of the RGB and CMY subpixels based on the determined video mode. It is achieved by a display device including a control unit.

The RGB and CMY subpixels are arranged in a 2 × 3 matrix, and each subpixel preferably forms a triangle in order to be less affected by color reproducibility of the pixel due to application of a black voltage.

The controller controls the driving circuit unit to apply a black voltage to the CMY subpixel when the image mode of the video signal is an RGB mode, and blacks the RGB subpixel when the image mode of the video signal is a CMY mode. The driving circuit unit is controlled to apply a voltage. Therefore, when displaying an image such as the primary color, the RGB mode is judged and a black voltage is applied to the CMY subpixel to reproduce a clearer image. When the intensity of the intermediate color is stronger than the primary color such as a human face, the CMY mode is used. The image signal is applied only to the CMY subpixels, and the black voltage is applied to the RGB subpixels.

On the other hand, the object of the present invention comprises the steps of converting a video signal received from the outside into a video signal of RGB and CMY; Determining a video mode of the received video signal by detecting a color intensity of the converted video signal; The method may also be achieved by a control method of a display apparatus including applying a black voltage to any one of the RGB and CMY subpixels based on the determined image mode.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

A liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram of a display apparatus according to an exemplary embodiment of the present invention, which includes a thin film transistor substrate 300 including a pixel, an image signal converter 100, a controller 250, and a driving circuit 200. 2 is a diagram illustrating a subpixel for an image mode according to an embodiment of the present invention.

Although the present embodiment has been described with respect to the thin film transistor substrate 300 of the liquid crystal display device among the display devices, the type of display device is not limited to the liquid crystal display device as long as the display device converts the image signal received from the outside into six colors. .

The liquid crystal display device includes a liquid crystal panel including a thin film transistor substrate 300, a color filter substrate (not shown) and a liquid crystal layer injected between both substrates, a driving circuit unit 200 for driving the liquid crystal panel, and received from the outside. And a video signal converter 100 for converting the video signals into video signals of six colors.

First, the thin film transistor substrate 300 includes a gate line 311 formed on the substrate material and a data line 321 crossing the gate line 311 and defining the subpixels 331 to 336. At the intersection of the gate line 311 and the data line 321, a thin film transistor T for transmitting the driving signal transmitted from the gator line 311 and the data line 321 to the subpixels 331 to 336 is formed. .

The gate metal layer including the gate line 311 and the gate electrode (not shown) of the thin film transistor T may be a single layer or multiple layers. The gate metal layer may include a silver-based metal such as silver or a silver alloy having a low resistivity, or an aluminum-based metal conductive film such as aluminum or an aluminum alloy. The gate metal layer may have a physical, chemical, It may further comprise a film made of chromium, titanium, tantalum, molybdenum, alloys thereof, and the like having good electrical contact characteristics.

A gate insulating film (not shown) made of silicon nitride (SiNx) or the like is covered on the gate metal layer.

The data metal layer including the data line 321 crossing the gate line 311 and the data electrode of the thin film transistor T is provided to be insulated from the gate metal layer. The data metal layer, like the gate metal layer, may be formed in multiple layers to compensate for the shortcomings of each metal or alloy and to obtain the desired physical properties. In the case of forming multiple layers, the data lines are formed of triple layers of molybdenum, aluminum and molybdenum.

Each of the subpixels 331 ˜ 336 includes a thin film transistor T, which is a switch element connected to an intersection point of the gate line 311 and the data line 321, and a liquid crystal capacitor Clc (not shown) connected thereto. Capacitor Cst (not shown). Six subpixels 331 ˜ 336 form one pixel area 330, and the pixel areas 330 are repeatedly arranged in a row direction and a column direction. Here, the holding capacitor Cst is an optional element that can be omitted as necessary.

A passivation layer is formed between the data metal layer and the physical pixel electrodes forming the subpixels 331 to 336, and the thin film transistor T and the subpixels 331 to 336 are formed by contact holes (not shown) formed on the passivation layer. ) Is electrically connected.

As shown in FIG. 1, the subpixels 331, 332, 333, 334, 335, and 336 electrically connected to the thin film transistor form one pixel region 330, and such one pixel region 330. Indicates a dot which is a unit for displaying an image. The six subpixels 331 to 336 are arranged in a 2 ㅧ 3 matrix, and the first row has a red (R) subpixel 331, a magenta (M) subpixel 335, and a blue (B) subpixel. 333 is arranged, and in the second row, a cyan (C) subpixel 334, a green (G) subpixel 332, and a yellow (Y) subpixel 334 are arranged. The RGB subpixels 331, 332, 333 form an inverted triangle over two rows, and the CMY subpixels 334, 335, 336 also form a triangle over two rows. When an image is input from the outside, an image signal is applied to only one of the RGB subpixels 331, 332, and 333 and the CMY subpixels 334, 335, and 336, and a black voltage, which is a black signal, is applied to the other.

The color arrangement of the subpixels is not limited to the above-described ones, and the six subpixels 331 to 336 are arranged in a row in the extending direction of the gate line 311, rather than in the form of a 2 ㅧ 3 matrix, or in a 3X2 matrix form. It may be arranged. In addition, one of the six subpixels may include a white subpixel to improve luminance.

The gate driver 210 may also be referred to as a scan driver. The gate driver 210 may be connected to the gate line 311 to receive a gate signal formed by a combination of the gate on voltage Von and the gate off voltage Voff from the driving voltage generator 230. Applied to the gate line 311.

The data driver 220 may also be referred to as a source driver. The data driver 220 receives a gray voltage from the gray voltage generator 240 and selects a gray voltage under the control of the controller 250 to provide a data voltage to the data line 321. Is authorized.

The plurality of gate driving integrated circuits or data driving integrated circuits may be mounted in a tape carrier package (TCP) to attach TCP to a liquid crystal panel, or may be directly attached to the substrate material without using TCP. A chip on glass (COG mounting method) and a circuit performing the same functions as those integrated circuits may be integrated in a liquid crystal panel.

The driving voltage generator 230 generates a gate on voltage Von for turning on the thin film transistor T, a gate off voltage Voff for turning off the thin film transistor T, and a common voltage Vcom applied to the common electrode.

The gray voltage generator 240 generates a plurality of gray scale voltages related to the luminance of the liquid crystal display.

The controller 250 generates control signals for controlling operations of the gate driver 210, the data driver 220, the driving voltage generator 230, the gray voltage generator 240, and the like. The data driver 220 is supplied to the data driver 220 and the driving voltage generator 230.

The video signal converter 100 converts three color video signals input from the outside into six color video signals of red, green, blue, cyan, magenta, and yellow. The video signal converter 100 has logic for performing an operation for converting the video signal. Such video signal conversion methods include a mixed color method of mixing three color video signals into a cyan video signal, a magenta video signal, and a yellow video signal, and a pure color method of converting a pure cyan, magenta, and yellow video signal into a non-mixed color. have. For the white signal, both methods use all six colors to obtain maximum luminance.

Brief description of the mixed color method of the above method is as follows. When a tricolor video signal is input from the outside, the magnitudes of the input tricolor video signals are classified into maximum, middle and minimum sizes. Here, the magnitude refers to the brightness or gradation of the video signal, and will be appropriately used hereinafter without division. Then, the video signal classified in size is decomposed into six color video signal components of R ', G', B ', C, M, and Y. The scaling factor is determined based on the three-color video signal and the resolved six-color video signal, and then the external video signal is converted into the six-color video signal by multiplying the scaling factor by the resolved six-color video signal.

The controller 250 is an input control signal for controlling the tricolor image signals R, G, and B and its display from an external graphic controller, for example, a vertical synchronizing signal, Vsync), a horizontal synchronizing signal (Hsync), a main clock, a data enable signal (DE), and the like.

The controller 250 detects the color intensity of the image signal converted from the image signal converter 100 and determines whether the mode of the input image signal is an RGB mode or a CMY mode based on the color intensity. Signals for natural images such as mountains and rivers have strong primary colors of RGB and crowded people, so CMY has a relatively high intensity for images with high skin color ratio. Accordingly, the controller 100 selects a mode according to the color intensity of the converted video signal and applies a differential control signal for driving the subpixel according to the mode. The controller 100 may further include a detector configured to detect an image signal color intensity.

If the RGB color intensity of the external image signal is determined to be the RGB mode, the controller 100 applies the image signal RGB to the RGB subpixels 331, 332, and 333 as shown in FIG. 2A, and the CMY subpixel ( 334, 335, and 336 are applied with a black voltage.

In the present embodiment, the liquid crystal layer positioned between the thin film transistor substrate 300 and the color filter substrate (not shown) is normally aligned (VA) mode, and normally black, which realizes a black screen without a voltage applied thereto. black). The liquid crystal molecules (not shown) lie in a direction perpendicular to the electric field because the liquid crystal molecules have negative dielectric anisotropy when a voltage is applied. In the state where no voltage is applied, the liquid crystal molecules are vertically arranged in the longitudinal direction to block light from the polarizing plates arranged in the opposite directions. Therefore, the black voltage applying the black signal is implemented by not applying the voltage. In other words, in the RGB mode, the controller 100 controls the data driver 220 to apply zero voltage to the CMY subpixels 334, 335, and 336.

On the contrary, if it is determined that the color intensity of the image signal applied from the outside through the detector or the like is strong, the image signal is applied to the CMY subpixels 334, 335, and 336 as shown in FIG. 2B, and the RGB subpixels 331 and 332. And 333, a zero voltage which is a black voltage is applied.

When a zero voltage, which is a black voltage, is applied to the subpixel, the color of the subpixel to which the zero voltage is applied is not implemented in the liquid crystal panel. As a result, an image signal is applied only to a specific subpixel having a large intensity, so that the display device can display a clearer and more realistic image.

In the case of the display device according to the present exemplary embodiment, zero voltage is applied to black voltage because it is normally black, but in the case of normally white white, the maximum voltage is applied to form a black voltage.

The controller 100 may further include a switching unit to select one of the changed image signals to be input to the data driver 220 and provide a user interface for selecting a desired image mode. Do.

The controller 250 emits the gate control signal CONT 1 to the gate driver 210 and the driving voltage generator 230 based on the control input signal, and converts the image signal R ′ from the image signal converter 100. G'B 'or CMY and the data control signal CONT 2 are sent to the data driver 220. The R ', G', and B 'video signals are video signals obtained by transforming R, G, and B input from the outside, and the C, M, and Y video signals are video signals newly generated by the video signal converter 100.

The gate control signal CONT 1 is a vertical synchronization start signal STV that indicates the start of the output of the gate-on pulse (gate-on voltage section), and a gate clock signal CPV that controls the output timing of the gate-on pulse. ) And a gate on enable signal (OE) that defines the width of the gate on pulse.

The data control signal CONT 2 applies a corresponding data voltage to the horizontal synchronization start signal STH indicating the start of input of the image signal R'G'B 'or CMY and the data line 321. Include a load signal (load signal, LOAD or TP).

First, the gray voltage generator 240 supplies the gray voltage having the voltage value determined according to the voltage selection control signal VSC to the data driver 220.

The gate driver 210 turns on the thin film transistor T connected to the gate line 311 by sequentially applying a gate on voltage Von to the gate line 311 according to the gate control signal from the controller 250.

At the same time, the data driver 220 according to the data control signal CONT 2 from the controller 250. The image signal R'G'B 'or CMY corresponding to the subpixels 331 to 336 connected to the turned-on thin film transistor T is input, and each of the gray voltages from the gray voltage generator 240 is input. By selecting the gray scale voltage corresponding to the image signal R'G'B 'or CMY, the image signal R'G'B' or CMY is converted into the corresponding data voltage.

The data signal supplied to the data line 321 is applied to the corresponding subpixels 331 ˜ 336 through the turned on thin film transistor T. In this manner, the gate-on voltages Von are sequentially applied to all the gate lines 311 during one frame to apply data signals to all the subpixels 331 to 336.

3 is a control flowchart illustrating a control method of a display apparatus according to an exemplary embodiment of the present invention.

First, the image signal converter 100 converts an image signal received from the outside into RGB and CMY image signals (S10).

The converted video signal is transmitted to the controller 250, and the controller 250 detects color intensity of the input video signal (S20) and determines a video signal mode (S30).

If the color intensity of the RGB image signal is stronger than that of the CMY image signal and is determined as the RGB image mode, the control unit 250 controls the data driver 220 to control the black signal in the CMY subpixels 334, 335, and 336. Is applied, and an image signal is applied to the RGB subpixels 331, 332, and 333 (S40).

On the other hand, when it is determined that the CMY image mode is not the RGB image mode, the data driver 220 applies a black signal to the RGB subpixels 331, 332, and 333 and an image to the CMY subpixels 334, 335, and 336. Apply a signal (S50).

Although some embodiments of the invention have been shown and described, one of ordinary skill in the art will be able to vary the driving of subpixels in accordance with the characteristics of the video signal without departing from the principles or spirit of the invention. It will be appreciated that this embodiment may be modified. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

As described above, according to the present invention, a display device having improved color reproducibility and a control method thereof are provided.

Claims (5)

A video signal converter for converting a video signal received from the outside into a video signal of RGB and CMY; A plurality of pixel regions including RGB and CMY subpixels; A driving circuit unit applying a driving signal to the pixel region; Detecting the color intensity of the converted video signal to determine a video mode of the received video signal, and controlling the driving circuit unit to apply a black voltage to any one of the RGB and CMY subpixels based on the determined video mode. Display device comprising a control unit. The method of claim 1, The RGB and CMY subpixels are arranged in a 2 × 3 matrix, And each sub pixel is formed to form a triangle. The method of claim 1, And the controller controls the driving circuit unit to apply a black voltage to the CMY subpixel when the image mode of the image signal is an RGB mode. The method of claim 1, And the controller controls the driving circuit unit to apply a black voltage to the RGB subpixel when the image mode of the image signal is a CMY mode. In the control method of the display device, Converting a video signal received from the outside into a video signal of RGB and CMY; Determining a video mode of the received video signal by detecting a color intensity of the converted video signal; And applying a black voltage to any one of the RGB and CMY subpixels based on the determined image mode.

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